[Mech Spec]

Hello All,

Just putting up this build thread and looking to get a central place to document the things I am doing to the car and also what I am doing with the car.

Chronological Build List:

Skid Plate - ------- Turner With DIY SS Mesh
Winter Wheels --- Superspeed RF05RR 19x8.5 et25
Tires -------------- Pirelli Cinturato Weatheractive 245/40/R19
Tint --------------- Llumar Ceramic 40%
Ceramic coating -- Cquartz Diamond
License Plate------ Sto'n'sho ACC compatible (mounted into skid plate)
(REMOVED)Lid Spoiler -------- AutoID TRE ID-01
Mirror Caps ------- RW Carbon
Reflector Delete -- IND Painted Reflectors
Rear Badge ------- IND Gloss Black BMW OEM
Mud Flaps -------- TLG Fender Guards
Emblems ---------- IND Carbon Painted Roundels
Paddle Shift ------- JQWerks Madtrace Carbon Paddles
Start Button ------ Kies Crystal
Floor Mats --------- TuxMats
(REMOVED) Springs --------- Dinan Lowering Springs w/ Bump stops
Spacers ----------- Future Classic 12.5mm 66.6 5x112
(REMOVED) Intake 1 ----------- Burger Drop in filter and Muffler Delete
Radar Detector --- Uniden R7 w/ Vortex Settings
(REMOVED) Exhaust 1 --------- AA Axle Back
(REMOVED)Aux Grille 1 -------- Aliexpress
Aux Grille 2 -------- RW Carbon
Exhaust 2 ---------- Eisenmann M240 Axle Back
Intake 2 ----------- RK Tunes Front Mount Intake
Heat Shield -------- Verus Engineering B58 Turbo Heat Shield.
Front Thrust Arms-- OEM w/ Turner Spherical Bushings
Front LCA----------- Hardrace
Coilovers ----------- Bilstein EVO SE adaptive coil system
Front Splitter ------- AutoID TRE ID-01
Lid Spoiler #2 ------ Turner Gloss Black Spoiler, Paint Matched.
DRLs ---------------- Amber Aliexpress (full heatsink version)
Downpipe --------- Fabspeed Catted
Door Projectors - Openthrottle M240
Speakers -------- Focal BMW Center/Door/Tweeter/Subs

-- Not Yet Installed--

Heat Exchanger - Dinan Low Temp Upgraded
Tie Rod Ends - SPL Bump Steer
Brake Pads - iSweep 2000
Brake Lines - HEL SS braided lines
Brake Fluid - Castrol SRF
Wheels - 19x9.5et25 Custom 10-Spoke Forged Wheels
Tires - 265/35/19 Continental ECS02
Valve Stems - Apex low profile
Center Caps - iND Carbon Painted floating 68mm center caps
Midpipe - Chinesium Resonated Midpipe.





And a few pictures of how the car currently sits.

[Mech Spec]

Reserved 1 - Cosmetics

[Mech Spec]

Suspension plan:

I started out with the Dinan lowering springs and bump stops. While I am happy with the ride height, and overall performance I decided that I would like to go further with the suspension and do a full revamp. On Saturday I discovered that that shop that I used to install my springs didn't replace any of the hardware that was used for the install. My strut mount bolts on the front right weren't tight on 2/4 bolts. These bolts are torque to yield and if properly installed cannot be loose. I'm now in a position where I can't trust the suspension as currently set because there are a number of torque to yield and one time use parts that I know were likely not replaced. As I had already planned to do full front control arm upgrades, I had about half the hardware to remedy this issue in my possession already.

Main parts to install:

Bilstein Evo SE Coilovers - https://cart.bilsteinus.com/complete-kit-49-305135.html
Turner Monoball Front Thrust Arms - https://www.turnermotorsport.com/p-2...nstalled-arms/
Hardrace front lower control arms - https://hardraceusa.com/products/fro...ries-g22-23-26

Hardware to be replaced:
Front
8x BMW Suspension Strut Assembly Bolt - BMW-07146884194
2x BMW Axle Bolt BMW-31206866022
2x BMW Suspension Control Arm Bolt BMW-31106885777
2x BMW Control Arm Bolt BMW-07119906460
2x BMW Suspension Control Arm Nut BMW-31106867397
2x Strut Mount Bolt 07146887408
4x BMW Hex Nut BMW-07119905307
4x BMW Combination Nut BMW-33306787062
4x BMW Control Arm Locking Nut BMW-33326760668
(Some extra nuts in there)

Rear

2x 33-50-6-889-267 Shock Mount - (BMW 3 series new rev mounts to fix OE rear clunk)
2x Cap - BMW (33-50-6-877-738)
4x BMW Control Arm Locking Nut BMW-33326760668
2x BMW Control Arm Bolt BMW-33326762875
2x BMW Suspension Control Arm Bolt BMW-07119908024

I installed the coilovers and control arms for my car this weekend. The job required many tools and took me around 8 hours to complete when going very slow to ensure I did every step correctly.

All one time use hardware was replaced, and torqued to spec including marking each bolt for TTY angle tightening and noting the final positions.

With the Dinan springs I had significant noise over various road imperfections. The small imperfection clunk I was able to resolve by tightening my strut mount bolts, but another front suspension clunk remained prominent and unacceptable. While I can’t say for sure if the install was the problem or the springs, I made the decision to convert to coilovers and be done with clunk hunting.

I also installed the 3 series rear shock mounts that are used to resolve the rear end clunk. Of note, all of the OEM dampers on my 2025 car were Monroe brand dampers.

Post install impressions:

Suspension noise: All my suspension noises are gone, the car is completely silent over any and every type of road imperfection.

Suspension Performance: Overall the coilover system is stiffer. In comfort mode I would describe it as in between OEM comfort and sport mode, with significantly tighter body control. Sport mode is now “track” mode and while the coilover dampers retain good low-speed compliance the high-speed damping is firm. I will likely spend most of my time in sport individual with comfort suspension setting.

Steering Performance: The upgraded control arms really tightened up the steering response and added back steering feel that was missing in the OEM setup. I have not observed any additional NVH from the control arm upgrades. I suspect that if I added solid tie rod ends would also improve steering feel further but may significantly increase NVH.

Installation Notes:

I used the FCP Euro G20 suspension videos as my guide to complete this job. They are very complete and do a much better job of describing what to do than I ever could. I have made a playlist of the 3 videos you need linked below.

https://youtube.com/playlist?list=PL...pAhfF7FoTq8NeD

I suggest that anyone using these videos as a guide also makes a written guide for themselves from the videos. Be sure to note order of operations, bolt sizes and torque specs.

My tips from doing the job:
- I removed all four wheels from the car and prepped all four corners (removing fender liners, sensors, wire mounts etc.) before starting anything.
- Some sort of mobile tool cart would have been very nice to have and would have sped up my install
- You must have a full size ½” torque wrench with a flex head like this one: https://www.harborfreight.com/12-in-...nch-56470.html
- After releasing the axle bolt in the front, crack all of your high torque nuts and bolts before you remove anything.
- IMO, must have an electric ratchet to do this job easily. I used a Milwaukee insider ratchet and it was invaluable.
- A solid selection of sockets (short, long, integrated u-joint) is needed
- Removing the strut from the knuckle I used this tool, it was incredibly helpful compared to a normal knuckle spreader, especial ly in the aluminum knuckle https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
- Also use WD-40 for the strut removal and re-assembly
- In the rear, a long 3/8” extension can be used to align and guide in the knuckle bolt during re-assembly. It’s nearly guaranteed that the bushing will not be aligned.

All Tools Used

[Mech Spec]

Reserved 3 - Powertrain

Installed RKtunes Front mount intake.

• No bumpewr removal needed
• Tight fit but works fine
• Will be able to replace filter without removing any parts.

- Remove all the stuff on top of the radiator stack, including the silver cross brace that the Vbrace attaches to.
- Remove the active grill shutter motor for easier access to the area
- Remove OEM intake and snorkel. To remove the snorkel you have to break it down into its two pieces in place (tricky)
- Remove snow guard and trim the plastic/rubber shroud to make room for the intake tube
- Pass the 90deg elbow section into the front from the engine bay. Takes quite a bit of squishing and working and elbow grease.
- Attach all the pieces including the filter and get the intake fully in place so that you know the filter and front tube are in their final position.
- Re attach the silver cross brace without fully tightening the screws then the V brace, fully tightened.
- Install the cooling stack cover and squish everything together, its a tight fit.
- Reinstall everything you removed.

My install took about 2hours but mostly because I was being careful since I had no instructions on what to do.

Could probably replace the filter in 45 mins tops. I bought an extra filter to swap in so that I can clean the used one without needing it to re-assemble everything.









Added the Verus Heat Shield which you can read about here: https://www.verus-engineering.com/bl...sting-data-105




Fabspeed HJS Downpipe Received.

[Mech Spec]

Reserved 4 - Interior/Audio

[Ricochet48]

2025 Thundernights look especially great with the painted skirts.

That intake is clearly the best performance as it's actually sucking in cold air, but as noted, replacing the filter would be much more work.

Excited to see more pics as time goes on!

[Mech Spec]

Originally Posted by Ricochet48

2025 Thundernights look especially great with the painted skirts.

That intake is clearly the best performance as it's actually sucking in cold air, but as noted, replacing the filter would be much more work.

Excited to see more pics as time goes on!

Thanks! I probably wouldn't have purchased an M240 if they kept the black accents. They made a very good decision removing that design.

I gotta say the car feels faster now... with the intake and the exhaust it's definitely noticeable, but since each part go put on incrementally it is a bit hard to tell.

[Mech Spec]

Skid Plate install and pictures:

Parts:
- SS wire mesh (5 mesh density)
- 3/16" x 3/8" Aluminum pop rivets (I used the wrong size)
- 3/8" SS Washers for spacing the aft plate away at the bolts


If using the wire mesh, its probably important to terminate the wire ends as seen in my picture

I used 3/16dia 1/2" long normal head aluminum rivets, its worked fine but I do not suggest using 1/2" length as I was forced to trim and round every single rivet.

All the tools I used. MUST WEAR GLOVES haha

[curtdragon]

Looks great! Sound clips of exhaust from outside driving?

[Mech Spec]

Originally Posted by curtdragon

Looks great! Sound clips of exhaust from outside driving?

Thanks!

I'm working on a plan for the exhaust video.

2 Things in the way: Video while driving is all wind noise on my phone, and my phone's microphone does not seem to be capable of accurately capturing the exhaust.

Looking to get a friend to run the camera, and use a quality microphone to capture the sound. Will hopefully do that soon and before I put on my downpipe.

[curtdragon]

Originally Posted by Mech Spec

Thanks!

I'm working on a plan for the exhaust video.

2 Things in the way: Video while driving is all wind noise on my phone, and my phone's microphone does not seem to be capable of accurately capturing the exhaust.

Looking to get a friend to run the camera, and use a quality microphone to capture the sound. Will hopefully do that soon and before I put on my downpipe.

Appreciate it. I’m trying to decide on Milltek, Remus Dinan or this. Akrop is nice but no way I’m spending double all the others.
Will also do a MAD catted downpipe.

[Mech Spec]

Originally Posted by curtdragon

Appreciate it. I’m trying to decide on Milltek, Remus Dinan or this. Akrop is nice but no way I’m spending double all the others.
Will also do a MAD catted downpipe.

Based on my research in exhausts:

Any exhaust without 2 valves and 2 straight pipes will be pretty quiet on this car. I returned my AA partially because it was too loud/drone in quiet mode and too quiet on the outside in loud mode.

Milltek - great bang for buck but not as good fitment/quality as they used to have. Their exhausts tend to be less refined in general (I had one on my 2015 R)

Remus - refined but quite quiet and hard to notice a difference from stock. If you want stock sound levels but better tone they are a good option.

Dinan - seems good, I might go for turner if I was looking at this one. Cheaper for nearly the same design.

The problem I have with almost every exhaust is that their tips are just subpar. Not designed well or not high quality looking, don't match the bumper of the car. Anything with a straight cut tip is going to look weird. It played a big factor in choosing the Eisenmann system.

[curtdragon]

Originally Posted by Mech Spec

Based on my research in exhausts:

Any exhaust without 2 valves and 2 straight pipes will be pretty quiet on this car. I returned my AA partially because it was too loud/drone in quiet mode and too quiet on the outside in loud mode.

Milltek - great bang for buck but not as good fitment/quality as they used to have. Their exhausts tend to be less refined in general (I had one on my 2015 R)

Remus - refined but quite quiet and hard to notice a difference from stock. If you want stock sound levels but better tone they are a good option.

Dinan - seems good, I might go for turner if I was looking at this one. Cheaper for nearly the same design.

The problem I have with almost every exhaust is that their tips are just subpar. Not designed well or not high quality looking, don't match the bumper of the car. Anything with a straight cut tip is going to look weird. It played a big factor in choosing the Eisenmann system.

Thanks for the insight. Dinan was probably my choice because of the cost. From the bunch Akrop sounds the best but not spending that money only for sound. I have yet to really hear many Eisenmann and Remus and Milltek sound similar but I thought the tips looked best on both those. Milltek I believe has a single tip that splits into two for each side that I though was neat. Makes it easy to align.
Once you got those sound clips up I’ll have a better idea of what I’m going with.

This whole platform is a lot of decisions on higher price better quality or lower price still good quality stuff lol.

[Mech Spec]

Updated my suspension plan above. Install this weekend assuming no surprise shipping delays.

[Mech Spec]

Weekend coming in hot!

[curtdragon]

Originally Posted by Mech Spec

Weekend coming in hot!

I looked this up and didn’t see an application for M240

[Mech Spec]

Originally Posted by curtdragon

I looked this up and didn’t see an application for M240

Same part numbers for g20. 49-305135, just not well updated on the web.

Essentially our entire suspension is shared with the g20.

[wb8164]

Originally Posted by Mech Spec

Updated my suspension plan above. Install this weekend assuming no surprise shipping delays.

Are you doing the suspension work yourself, and if so do you have access to a lift or or are you doing it on jack stands?

[Mech Spec]

Originally Posted by wb8164

Are you doing the suspension work yourself, and if so do you have access to a lift or or are you doing it on jack stands?

Yes DIY. FCP euro has posted full guide videos for the g20.

I should say, I'm pretty experienced at wrenching and have a ton of tools, so it's not like I decided to do this out of the blue.

Jack stands. Nothing about this job particularly necessitates a lift.

[kudos]

In the first picture you posted, I believe it was Dinan suspension with 245/40/R19 and 12.5 spacers. Did you have any rub? I was going to go 245/35/R19 but if I can go bigger then even better.

[Mech Spec]

Originally Posted by kudos

In the first picture you posted, I believe it was Dinan suspension with 245/40/R19 and 12.5 spacers. Did you have any rub? I was going to go 245/35/R19 but if I can go bigger then even better.

It rubs on the inner fender liners at 80%-full lock in reverse. Pretty much dont notice. Yes that tire and wheel spec is correct.


As you can see I have elected to remove my dinan springs as they are not performing to my liking. I apologize if I led you to buy them with my initial positive impressions.

[curtdragon]

Originally Posted by Mech Spec

It rubs on the inner fender liners at 80%-full lock in reverse.


As you can see I have elected to remove my dinan springs as they are not performing to my liking. I apologize if I led you to buy them with my initial positive impressions.

But was the hardware or poor install that you have issues with?
I thought about full suspension but I like the sound of adaptive dampers and not sure I want a rough ride all the time.

But I wish you were doing it on the stock suspension parts so I could hear your thoughts about the coilovers. Are you planning on tracking the vehicle? Sorry if I missed that.