Chopsuey’s 2025 Civic Si Build Thread

[chopsuey34]

OEM+ “NA” build

(In this thread, we don't just build cars but relationships with them, too. Read on past the modding to get to the stories.)

My goal is to put some money into my Si and turn it into “what it should have been from the factory”. But in doing so, I don’t want to fundamentally change its character or power. If I wanted something more powerful or different, I would have just bought that something else.

This is my first Honda. I’m not a Honda guy, and I’m not a VTEC, 90’s golden era Honda fan boy, either. I also don’t like torqueless, high revving engines, the kinds that Honda was famous for building back in the day. But I am an “NA” guy, and this is my first turbo.

With my build, I want to replicate a naturally aspirated engine, meaning I want as much throttle response and as little turbo lag as possible. I also want to avoid the temptation of abusing the turbo and turning the L15CA into a torque monster with a camel hump dyno sheet. Instead, I want to aim for a “mini V6” feeling that I believe the 1.5T is capable of: more, linear power. And in fact, I don’t need much more power at all. I’d rather some more response than anything. I’d rather use 100% of 200hp (or 220hp) than 70% of 315hp.

Good opinions and new points of view are always welcome (please be civil, though)

I’m using this thread as an information dump for myself as well FYI.

I hope you enjoy this build.

Engine
PRL Rear Motor Mount (PRL-HC11-RMM) – great!
PRL Resonator Delete Kit (PRL-HC11-RES-KIT) – useless
PRL 1.5T Silicone Intake Hose Upgrade (PRL-HC11-15T-INT-HOSE) – useless
Sprint Air Filter (P1137S) – a little more power, maybe?

Cooling
PRL Intercooler (PRL-HC11-IC) – haven’t heat soaked yet!
HPT WOT Performance Cool Plate (FL5/FE1) – high quality

Tune
Stock Tune (Phearable 1.5R planned for Spring 2026)

Transmission / Shifter
Acuity Stage 2 Shift Kit – love it
Throttle Pedal Spacer (Acuity #1919) – hated it, uninstalled & returned

Suspension
PRL Rigid Collar Kit (PRL-HC11-SRS) + Alignment – not sure if I can feel the difference

Wheels
Enkei TS-5 18x8.5 +38 (Bronze)
Continental DWS06+ 245/40R18
45.2lbs vs. 52.6lbs stock (~30lbs unsprung weight saved)
- Stock size for reference – 18x8 +50, 235/40R18, 5x114.3


Exterior
Honda Black Emblems (08F20-T20-100) – only rear badge applied
Honda Door Edge Film (08P20-T20-100A)
Honda Door Handle Film (08P48-T20-100)
Honda Rear Bumper Applique (08P48-T20-100A)
Honda Door Sill Metal Protection Film (08F05-TVA-100)
Honda Side View Mirror Covers (76251-T20-A01ZB & 76201-T20-A01ZB)
Honda “Tear Ducts” (71202-T61-A51ZE & 71207-T61-A51ZE)
LASFIT LED Bulb Turn Signal Light Amber (T3-7443A) – well-known brand in CivicX and CivicXI communities
LASFIT LED Bulb Reverse (Light L-T15)
Sukeban Mudflaps (Deluxe Black) – good product

Interior
Honda Cargo Hooks (08L96-TA0-101A) – useless, plastic grocery bags from Meijer aren’t tall enough
Dash Cams (Front & Rear – Rove R2-4K Dual) – satisfied
LASFIT LED Bulb Trunk Light (L-T10)

Accessories
Honda Euro Horn (08P80-T43-000) – sounds better than stock (“hoooonk” vs. “eeeeee”)
Tuxmat Floor Mats (Front #8701 & Rear #8701-T1) – high quality
Silicone License Plate Frame (Amazon)
Screen Protector (Amazon)



Future Mods:

Phearable Stage 1.5 RACE Tune – planning on running Map 1 exclusively because I drive like THIS. KTuner provides other updates like quicker turbo spool and disabling auto-stop.

Progress Tech Sway Bar (20.6mm, same as Type R) – maybe. I’m not even sure if I want this honestly. There are only 3 highway on-ramps in my city where I really feel the need for a thicker rear sway bar.
- Honda Accord End Links (Honda 52320-TLB-A00)

Spoon Springs (51400-FE1-001) – probably not, because this is a daily and I don’t want my car any stiffer. But these are the only springs I would run if I chose to do so because they are similar to stock and only drop an inch or less

Weighted Shifter?

 

[chopsuey34]

Review of the Si:

Brief history: In January 2024, I put down a $500 deposit on an Si. Literally the next day, Honda Corporate announces the Civic refresh. Damn. I spend the next month going back and forth whether to delay or purchase. I end up cancelling my 2024 Si and waiting a full year. I purchased my 2025 Civic Si in February 2025 a few weeks after Trump first announced the first round of tariffs. Got it at MSRP. In the first few minutes on the test drive, I hit some Michigan potholes, and the car was solid with zero rattles. I said to myself, “This is the car”.

I’m an NA guy. This 2025 Civic Si is my first turbo car. I'm already sick of turbos feeling lazy and weak in the heat, and then sharp and powerful at night when it’s cooler. I can slam and jam NA engines all day no matter the temperature or humidity. Turbos, however, like to load manage like NBA players, they work when they feel like it, those prima donnas (“I’ll manage my load into your mom” – see, turbos are moody, just like teenagers, yelling at them doesn’t work, I tried :/ ). One carries on, though.

FWD kind of sucks, but I’m ok with it. Michigan winters remind me every year why I don’t daily a RWD anymore like I used to.


Engine: I don’t have experience with turbo engines coming from an NA background. I like the torque in the low and mid-range. A 1.5L shouldn’t feel this powerful but it does! (The GR Corolla 1.6T must be a blast). I like the linear power of the engine; it builds like an NA engine and doesn’t fall off at the top end. I can get up to +100mph pretty easily, no complaints. Well done, Honda. But I’ll complain anyways: the total power output leaves more to be desired, and I know it can give me more (Imma tune that bitch up to 30psi with tariff free ‘Murika-grown ethanol, yee haw!).

Full throttle in this car is good, but a little underwhelming. Half throttle is great, strangely (turbo noobie can’t explain his thoughts).


Suspension: Rides great. Like a dream. For me, the body seems like it is just under the stiffness threshold where it would become too stiff. That’s why I hesitate to do springs and bracing. It’s a daily after all. The 22-24 Si is about 8% stiffer than the 10th gen Si, and the refresh Si is about 3% stiffer than the 22-24 models (more rigid front upper suspension mounts, front subframe mounts, B-pillar supports, and rear lower suspension mount supports – although, I’m sure no one would be able to feel the difference).

There’s some body roll on stock springs, of course, but body roll is fun. I don’t know if I want to hate myself and go any stiffer.


Handling: Driving is planted, no twitchiness, and tends towards understeer for safety as intended by Honda. No wheel hop because of LSD, great. On stock tires, I had torque steer, with DWS06+, don’t feel it anymore.


Exhaust: I’m an “NA” guy. I prefer an excellent exhaust note over turbo whoosh noises. The stock exhaust sounds great, but is a little quiet. I wish HKS distributed an exhaust for the FE1. There’s an HKS Thailand model that fits the FE1 (HKS 31013-ZH011), but that costs $2,350 all in to ship from Thailand. Definitely not doing that.

There’s the option of keeping the stock exhaust and swapping out the downpipe (either TSP, 27Won, etc.). But I’ve watched videos of those on YouTube, and I would hate myself if I burbled and popped on every upshift and downshift. Plus, I’m allergic to drone. Still deciding on this route.


Styling: I love the 11th gen Civic styling. Why? The 11th gen Si always reminds me of the 10th gen Accord, which is one of the best styled cars out there in my opinion. It also reminds me of a more understated German saloon, a 3-series or Audi A4/S4. Perfect. A strong line along the body. No awkward lines like in the Integra. Great, traditional sedan proportions (BMW’s long hoods are still better, though). So much better than the teenage anime freak show that was the 10th gen Civic (Honda will mess up the 12th gen Civic, mark my words). I saw a previous gen A6 in a parking lot next to a Civic Sport, and a German executive saloon with good lines and proportions and understated styling is what I aspire to in a daily (Accord first, though).

At first, the refreshed front grille was awkward to me in photos <insert Jay Leno or Crimson Chin joke here>. But now, the grille has grown on my, and I don’t think it has a bad angle. Without getting a slide deck out, I like the upper and lower grilles of the refresh better than the pre-refresh, but the pre-refresh “koi fish” cheeks are my favorite most of all.


Fog Lights: Fog lights are the biggest gimmick I’ve ever seen. I live in Michigan and see my fair share of fog, and I’ve never used fog lights in my life, on my previous cars, my parents’ cars, or my friends’ cars. I’m glad Honda ditched the fog lights for 2025 (schadenfreude - I enjoy hearing people whine about not having fog lights). By the way, the headlights on the Civic are great. I like them. They have a good pattern.


Sunroof: As an owner of a convertible, sunroofs make me lol. I don’t use mine often. Type R owners who complain about not having a sunroof are missing the point.


Driving Assists: My hands-free drive assist is great. Lane centering is good for road trips, but I rarely use it. When I do, it sometimes flashes a warning at me to put my hands on the wheel every 15 seconds, and sometimes every 75 seconds. I’ve had one “phantom truck” situation where the car detected a box truck in front of me and slammed the brakes despite there being an open highway in front of me.


Seats: I like the seats. No issues, I don’t need lumbar, but that would have been nice. I’ve sat in FK8 seats before, and those were phenomenal (but also hard to get out of – not a great characteristic of a daily driver). The worst seating experience I’ve ever had was in a Lotus Elise. I had to remove my shoes to get in and out of that car (I’m not obese btw, I have a six pack, pics or it didn’t happen).

I don’t care about not having dual zone climate control because the Civic has a small cabin, but the heated seats are great in the winter (California drivers don’t need heated seats, there I said it, you spoiled babies and your 45-degree chilly mornings).


Interior: I needed a daily, and this dash & infotainment are great. I love the tactile buttons (I will never buy a VW with the haptic buttons, no way man). I don’t mind the horizontal piano black garnishes surrounding the hex grille anymore. I’m very pleased with this purchase, and I’m glad I waited for a 2025 model. The extra features, like the fully digital dash, makes the Civic feel complete and a little more upscale. Road noise is a little high, but that’s alright by me. This isn’t an Audi. The interior is best in class, way better than WRX, way better than GRC, way better than VW (don’t get me started on that haptic scheiße). Mazda 3 not even considered because rear torsion beam, I mean, come on bro, who does that?


Color: Sonic Grey Pearl is my favorite color, hands down (Urban Grey Pearl, SGP’s cousin, is ok). Platinum White Pearl was my 2nd choice, but I ended up buying a white car for my mental health. I test drove an SGP Si with 5,000 miles on it, and the swirls were outrageous. I can deal with dirt on my car, but I can’t deal with scratches! White doesn’t hide dirt, but it does hide scratches well. My neighbor has a white 10th Gen Accord, and that thing still looks mint from 15 feet away.

 

[chopsuey34]

NEGATIVES:

Beyond the things I can change (tuning for some more power, etc.), the worst things are:

1) Android Auto (Google, not Honda). In July or August 2025, Google pushed an Android Auto update that… wasn’t great. I had lots of problems connecting wirelessly, but it seems the issues have fallen off with every update. Over wire, my audio is perfect, but over Bluetooth, my Android Auto freezes for half a second every third song. Very annoying. BOSE audio system is good, no complaints. The ELS in the Integra is better, but I’m not paying up for it.

2) The other thing I wish the Civic Si had are LED Turn Signals in the side view mirrors. That’s the only thing that really annoys me. My beater Scion xB from 2008 had turn signals in its side view mirrors. Damn, Honda. Focus groups and profits, my ass. I would have paid an extra $400 MSRP for those.

3) Can’t turn car from ON to Accessory mode without turning of engine, which interrupts music. I think this is a feature (bug) of a lot of push-start ignition cars, but it’s annoying when I pull into a parking lot and pause my music for 7 seconds after shutting the engine off to switch back to accessory mode.

4) I could use the heated steering wheel from the Integra during northern winters, yes.

5) There’s a “click” when I press the brake pedal in after a while of not using it. I think this is normal for all cars, but it seems louder than usual. In my previous cars, I couldn’t hear it as loudly. The Civic isn’t a luxury car, but that small click every time I depress the break pedal is a tad annoying.

6) Maybe a teeny bit more sound deadening wouldn’t have hurt as well.

7) The exhaust sounds great, but is a little quiet. But I’m not sure about going full cat back.

 

[chopsuey34]

Why did I buy the Si?

I work in finance, and this is my BWM 3 series replacement. No actually, it’s my Audi S3 replacement. I’m supposed to be in those kinds of cars now that I’m in my mid-30’s, but by the looks of it, I’m a decade behind because all I can afford is a Civic Si. I’m a banker. No, not that kind of banker, the kind who can only afford to drive a Honda. And as a banker, I need my executive saloon, but I don’t want to be a cock (as Jeremy Clarkson used to say), and this Honda fits the bill very well. No, I’m just kidding, I actually bought this car because:

While I’m still young and immature, this Si is my last “fun” car, a tribute to my youth and freedom before life inevitably hits. It had to be a stick shift, and I wanted something new. It’s my daily so the WRX was out (horrible infotainment), the BRZ (been there done that), the GR Corolla (hero powertrain, but Tonka toy interior – people seem to dump them after 5,000 miles), and the Integra (very underwhelming during my test drive – a Civic Sport drove better in my opinion). Watch Everyday Driver’s YouTube video on the Acura Integra (“The Beloved”) from 4:30-7:00 and about 12:00-15:00; they and I think alike, the Integra A-Spec is a disappointment to drive.

Why I didn’t get a Type R?

I like the sedan styling more than the hatch (although I like both), and the 11th gen Si always reminds me of the 10th gen Accord, which is one of the best styled cars out there in my opinion. I suppose I subconsciously wanted that executive sedan that 30-something finance types seem to buy.

I could have stretched for the Type R, but I think the extra $17,000 would have been wasted, plus I wanted to mod my car out and that’s another $6,000. I needed to scratch the itch of modding my next new car. If I had purchased a Type R, I still would have spent the extra $6,000 on top of the extra $17,000.

Also, the opportunity cost of paying for a CTR is $17,000 * 1.06 ^ 30 = $97,639.35. That's a lot of money to spend on a car once you consider compounding for your retirement.

The Civic Si is fast enough for me and the roads I drive on. The CTR would be complete overkill, I’m only on the street, I’m never taking it to the track or autocross. Slow car fast, really. SavageGeese ran a video about Endgame Cars and I think it applies to my situation: the extra $17k for the Type R isn’t going to 2x my fun, change my life, how I drive, and what I like. 10/10 in an Si is more fun for me than 7/10 in a Type R. Plus, nobody in my life gives a damn about my car except me, so I bought what I wanted and my brokerage account thanks me for it. One last thing is psychological: I’m sensitive about where I park my Si, so I would be doubly so with the CTR. I would be an nervous wreck all the time with that car leaving it behind in parking lots because I would be worried about dings and scratches to my little baby.

The Civic Type R for me is a vanity. And I want to rid my life of affectation. I can't even drive the Si to its full potential, so why then get the even more capable Type R? I also drive my Si hard, and if I drove a Type R that hard, I’d probably kill myself or go to prison.


Why are you modding a new car? Are you stupid? There are these things called warranties, dummy!

Yes, I know. Let me explain: When I was a teen, I was a mega computer and video game nerd, but my parents never let me play many games. I never got around to buying a gaming system or building a PC in college, either. Eventually, when my MacBook crapped out in 2019, I decided to build a gaming PC to scratch the itch that I never got to scratch. I built a good value gaming PC for $1,200, played two computer games, and haven’t gamed ever since.

This is the essence of what I’m doing with my Civic: I’m scratching an itch so I never have to do it again (in my research, most modding isn’t that useful for street use anyways, like I give a flip that I go 0.4 seconds faster to 60 in my neighborhood). It had to be done, now was the time, and I did it.

My risk tolerance is high, especially for the power levels I want. I’ve read a lot about tuning. I asked questions when I didn’t know something, couldn’t find it out, or wanted opinions from people more knowledgeable than me. I can take the financial risk as well. It’ll be a year and several thousand miles before I tune, so the engine and clutch will be broken in and bedded very well. And while I drive my cars, I don’t abuse them, and I don’t race people, so the temptation to do dumb stuff to win isn’t there, like dumping clutches or whatever. You know what, I’m guess I’m kind of smart and responsible with the things I buy.

My current garage is my 2025 Civic Si and my 2002 Toyota MR2 Spyder. Thinking about it, I don’t really need anything faster. I like lightweight, not power. Slow car fast. I’m tempted to downsize to a Honda Beat or a Suzuki Cappucino or similar because those cars are slow asf, but I like that (maybe a motorcycle, but I’d kill myself). Going full throttle in the Si for 10 seconds is fun, and slow cars keep me out of trouble. I want a Porsche, but they’re so expensive. Are they really worth the premium? Is a 911T really x3-x4 the fun? Will I ever use a 911T and be able to park it in public places and not worry about a scratch or ding? And when will I ever need 400hp on the street? I can go really fast with 200hp in my Si.

I would be very happy with an Accord Hybrid & Miata ND3 (NE1?) family man combo for a long, long time once I get married and have kids (lol fat chance, virgin beta)

 

[chopsuey34]

Fuel Economy

Normal driving with Michigan 93 is 32mpg, 1mpg above EPA estimates
I get 31mpg when I am more aggressive, and 30 mpg when really hammering it
+40mpg on 100% highway trips on summer gas

I am satisfied with my Civic’s fuel economy.

 

[chopsuey34]

Aesthetics (i.e. customizing my Civic):

I like the debadged look. Every car I own, I have ripped those things off and sometimes even the company logo. My Civic is no exception (with exception to the H Badge).

I applied the Honda black badge in rear and debadged the “CIVIC” and “Si” badges. Looks cleaner. There’s an Audi S3 that sits in front of a vape shop in my neighborhood that looks exactly like this. I used to think that the 11th gen Civics looks like BMW 3-series, but I now think they look like Audi S3’s.

I kept the silver Honda badge in front. I think the black badge hides in grille, and the silver one stands out more. To each his own. I also wanted to remove the red Si badge up front, but decided against it. Its a nice, subtle "beauty mark" that breaks up the white and black.

I changed the side view mirror covers from black to white for a more cohesive look. I never liked the way the black side view mirrors looked.

The more subtle thing I did was change the “tear ducts” from black to white. Again, I never like the way the black upper grilles on these cars stretches from side to side (the pre-refresh upper grille looks like a “racoon” to me). I installed these white tear ducts to add some definition and angles to the grille.

There’s an entire world of customization available with these tear ducts. I thought about doing an M car tribute with a blue tear duct on the left and a red one on the right. I also thought about red ducts-on-white, blue-ducts-on-white, and dune-brown-on-white. But I settled on the cleanest look with the white-on-white look.

Let me know what you think (don’t be a hater, please).

 

[chopsuey34]

Money Post – 2025 Civic Si

$31,855 – MSRP
$455 – Platinum White Pearl color
$1,150 – destination charge
$1,929.54 – Michigan 6% sales tax
$4,807.96 – Capitalized Interest @ 5.99%
$475 – dealer fees
20% down – conservatively financed

$34,250.54 OTD

I’m the only car guy in the world who doesn’t lie to himself. I track every penny I spend on my cars. I know exactly how much I spend on my cars. Sometimes I lie to others, but I will never lie to myself about this expensive hobby of mine. It helps me avoid being delusional about my cars but not completely.

My dealer didn’t cash my down payment check until 3 weeks later! I think the check lost itself in my customer folder and the finance manager forgot to deposit the check. Accounting must have had a meltdown wondering where the $6,000 hole came from.

Not sinking that much cash into this car, I’ve already spent around $6,000, and will spend about another $1,000. If I wanted to make this a monster, I would have just bought a Type R.

Total Mod Spend: $5,647.34

Performance – $161.49
Suspension – $286.97
Cooling – $981.93
Shifter – $534.47
Wheels – $1,948.53
Visuals – $556.87
Accessories – $1,177.08 (TuxMats, films, edge guards, etc. aren’t cheap)

Planned – Maximum of $1,200 including tune (maybe), rear sway bar (maybe), interior customizations

(No, I don’t want your opinion about financing and money, thanks. Take it out on your wallet or your significant other.)

 

[chopsuey34]

Break-In & Oil Changes:

Honda Engineers Have Internal Debates Regarding the Usefulness & Necessity of Break-In Oil Changes
https://www.civicxi.com/forum/threa...as-any-benefit-to-keeping-it-in-longer.54128/

BMW Official OEM Break-In Procedure:
https://www.bmw.com/en/automotive-life/break-in-a-new-car.html

Lotus Official OEM Break-In Procedure via Harry’s Garage (timestamp 11:00-13:10):



My BMW & Lotus Inspired Engine Break-In Procedure:

600 miles before crossing 4,000 rpm
1000 miles before hitting redline (max 5,000 rpms once oils are up to temp) – 1000 miles is the average between Honda, BMW, and Lotus recommended bed-in miles
Max 1/2 throttle (1000 miles) and 1/2 brakes (300 miles)
Change rpms more often than usual (downshifting, more city driving, no sitting at an rpm for 15+ minutes)
Always using car for +30 minutes to get oil temps up for first 600 miles

(No, I don’t want your opinion about oil changes, thanks. Take it out in one of the oil change threads that pop up every week)


Even Honda engineers debate the merits of changing the factory fill oil early. Even with the designers of these engines, there isn’t a consensus (I’m posting this a second time, so read it again, dammit)

https://www.civicxi.com/forum/threa...as-any-benefit-to-keeping-it-in-longer.54128/



BMW doesn’t recommend an early oil change, Lotus doesn’t recommend an early oil change, either (I’m not a conspiracy theorist, and I don’t believe they want to grenade your engine). Influenced as I was by this, I still changed my oil at 2,500 miles and 5,000 miles, and now I’m on a twice a year schedule (spring / fall) regardless of mileage.

Bedding your engine and transmission will lower vibrations, reduce cylinder wear, and prevent unnecessary oil blow-by over the life of the engine (make more power??).

If you don’t want to do any of this, just drive your car like a Camry for 600 miles, avoiding revving over 4,500 rpm and get more intense as you near 1,000 miles. (600 miles is Honda’s officially recommended break-in mileage). That’s about two tanks of gas, just be patient. After that, do whatever the hell you want to your car.

Don't overthink it (I did). It's a reliable Honda engine.


Also, I dug up these screenshots showing that Euro-spec 1.5T engines can use 5W-30:

 

[chopsuey34]

Oil Dilution:

We know 10th gen 1.5T engines suffered from this, especially in northern climates. The simple answer is that certain owners did not drive their cars for long enough to evaporate the gas that collects in the engine oil (naturally due to direct injection). Many short trips (think grammy going to the grocery store) over the winter is a recipe for oil dilution.

How to prevent oil dilution? Drive your car at least 30 minutes every so often to get the engine oil hot enough long enough to evaporate the gas out through the PCV system. Easy!


How Long It Takes for Your 1.5T to Warm Up (timestamp 15:15)
"The downside of downsizing - Oil dilution due to petrol" - ElektroPartnerApS
(YouTube Link not working for some reason)


In 50F (10C) ambient temperatures, it takes your 1.5T 15 minutes of highway driving and 18 minutes city driving to get up to 60C, at which point the gas in your oil will start to evaporate. People who experience oil dilution need to occasionally drive their cars longer than these amounts (depending on weather) to get the oil nice and hot, and they won’t experience any oil dilution anymore.


Total time for oil to get to 60°C (temp when gas starts evaporating) in a Euro-spec 1.5T engine (green color confirmed, blanks are my estimates)

 

[chopsuey34]

Cooling (Intercooler & Cool Plate)

Removing the bumper to install this was a pain in the ass, but doable.

3-month out of the year kind of mod here in Michigan, but I haven’t heat soaked yet and I drive aggressively. I don’t notice any extra lag on the street with the PRL intercooler and stock charge pipes.

I decided against the larger charge pipes because 1) my power level goals are mild and the extra capacity isn’t needed and 2) I was risking more lag with the increased diameter of the charge-pipes.

Cool plate from WOT is high quality. Its main purpose is to keep coolant temperatures down by providing additional venting from the engine bay. Had I purchased the WOT Cool Plate first, I may have skipped the PRL intercooler.

 

[chopsuey34]

PRL RMM

Great, highly recommended, for the first 50 miles, I was worried. I could feel the subframe vibrating, giving me essentially a massage in my seat. But it settled down and now feels great.

The stock RMM is very smooth, but gets buzzy above 5,000 rpm. The PRL is slightly buzzy on start up, and has a hint of vibration at idle (without A/C on), and remains smooth above 2,500 rpm. A little bit of give and take, but I’ll take it. The PRL RMM is one of the best things you can do to your Honda. It helps with sharper upshifts and downshifts, too. I notice that on throttle and off throttle response in the transmission is sharper, too.

During 2nd drive, vibrations settled done somewhat. Exhaust note growls a little more?

After 5th drive, I can't even feel the vibrations (basically feels like stock mount except it is smooth above 5,000 rpm) any more except when starting from a stop; slipping the clutch into first will have more vibrations

RMM has "moods" some days stiff, some days can't even feel -> it isn't really temp dependent

 

[chopsuey34]

Shifter

Bought in March/April 2025 (two months before the full shifter was announced. No plans on upgrading to Fully Adjustable for another $425 (the spacing is fine, and I don’t need the adjustability, and I don’t want to spend $425 for marginal gains)

Stock Shifter was stiff for first 100 miles, I was missing 5-6 frequently, but started to break in nicely after about 200 miles. The stock shifter was fully broken in after 500 miles, and there was a sweet spot at 300 miles where not too tight, and not too loose.

My stock transmission had no crunchiness, and my 1-2 shift has no issues. Maybe I am lucky? 10th gen dudes have lots of issues with the 1-2 shift.


Acuity Short Bushings:

Acuity Shifter bushings were installed separately for about a week before I installed the shift kit. Definitely a more mechanical feel, the stock shifter is good but still sometimes has that rubbery feel to it, especially in the 4-5 shift. Now that feeling is gone. Not a huge step in mechanical feeling, but noticeable enough. The "junctions" and direction changes of the shifter feel more solid and distinct.


Acuity Short Shift Kit Stage 2:

I had two concerns: this would make my shifts too close together (I like to row), and too stiff (mechanical, but not bolt action)

After a short break in period, the Acuity short shift kit is a very high-quality shifter and my concerns were addressed. I’m very satisfied and can't imagine the car without it now.

I purchased this 2 months before the fully adjustable full shifter was released. I like the spacing and don’t need the full adjustability, so spending $420 on the full shifter to me isn’t necessary.

 

[chopsuey34]

Rigid Collars

I have mixed feelings about my rigid collars. I can feel the slight stiffness, but now, the car suspension doesn't "float" like it used to (in a good way). I feel bumps more, the car seems to be more sensitive, and the car seems like it picks up bumps on the highway? (this is pre-alignment)

Alignment was then done at local Honda dealer back to stock settings (my usual place wouldn’t take the Civic, citing some BS reason about resetting computer systems). Car drives better than before, "crashiness" lessened, will give it a few days of driving to see

Two weeks after rigid collars and alignment – Car drives really well; but I'm not sure I can feel the rigid collars. Then again, I can’t remember how stock was like. But the difference isn’t that big.

I don't regret doing rigid collars, but I probably won't do them again on future cars. I noticed that the HRC FL5 race cars don’t use these at all. Could be for other reasons.


https://www.civicxi.com/forum/threads/spoon-vs-prl-vs-other-rigid-collars.61125/page-2

 

[chopsuey34]

Wheels and Tires

Enkei TS-5 18x8.5 +38 (Bronze)
Continental DWS06+ 245/40R18

2025 Civic Si stock wheels and tires weigh 52.6 lbs on my scale.
Enkei's & DSW weigh 45.2lbs
~30lbs unsprung weight saved.

After thinking for 2 years what kinds of wheels I wanted, the Enkei TS-5’s were the ultimate choice. I wanted that classic 5 spoke look, and these were the ones. I considered a few others (Konig Rennforms – very light, kind of rally look, but I eventually considered them too busy and difficult to clean). I’m glad with my eventual choice.

Dropping 8 lb per wheel per corner I can feel the car is more eager already especially when coming out of corners from a stop. The DWS06+ tires grip well, and there’s no wheel hop or torque steer with them, unlike the stock wheels.

On the street, these wheels don’t make that big of a difference (30lbs unsprung weight saved), but I love the way the car looks and that’s that. Unless I get a Miata, my next car will stay on stock wheels, and I’ll get high quality spacers and slightly wider and stickier tires instead of dropping $2,000+ for wheels and tires. Honda has dope ass 19” Accord rims.

Does Wheel Weight Really Matter? 20, 38 and 52lb wheels tested! - Tyre Reviews

 

[chopsuey34]

Sprint Air Filter + PRL Resonator Delete + PRL 1.5T Silicone Intake Hose Upgrade

I managed to scoop up a Sprint Filter used for $70 from a user on this forum. I haven’t used it too much because the driving season is ending. I’m not going full cold air intake because 1) I like all-motor and exhaust sounds more than turbo whooshes 2) I don’t like turbo whooshes.

Both 27WON and PRL admit the stock 11th gen intakes are very good and it was hard to improve on them. For my planned power levels, I don’t need to futz around with an intake when the stock one is already very good. Oh, and let me remind you, I also am an “NA” guy, and I couldn’t care less about turbo whoosh noises.

With the Sprint filter. I can hear “wind noise” above 5,000 rpm, not like a suuuuuuuck from a typical aftermarket filter (K&N) but like the wind is flowing past my ear (it’s hard to describe). Ososik ran a dyno and showed 8whp gain above 5,000 rpm (lines up with the "wind noises" I'm hearing. Ok, so there’s some proof, but it’s only above 5,000 rpm. Tracks well with other drop in filters from other cars. At least there’s no torque loss down low. FYI Spoon filters are rebadged Sprint filters with a huge markup.

After 4,500 miles, my stock filter is pretty dirty. I don’t plan to use the Sprint filter that much because of that, only for dedicated spirited runs. I wouldn’t want to run the Sprint filter long-term (I can see through it).

I don’t like oiled filters like K&N, and this Sprint filter is dry and good enough for me.

$70 itch scratched.


Both the PRL Resonator Delete + PRL 1.5T Silicone Intake Hose Upgrade are useless. I barely hear them at all. With the Intake Hose, I can’t feel any change in throttle response or any power, but intake noise sounds a tiny bit throatier, maybe. FYI it’s the filter that does all the work.

$50 itch scratched.


Sprint Filter Dyno per Ososik / FOAT Media:

Sprint Filters: