Immaculate low mileage 2004 Silver Grey CSL Inspired Build

[Keith_MN]

This car is the first time I’ve taken on a build project with kids, and I’m finding it really interesting. With young kids, projects seem to take 10x longer, but the final product has been 2x better than when I didn’t have kids. In general, I only have an hour or so a day to work on any given project. What this means is that the sessions are far more premeditated, and I never get to work on the project long enough to get frustrated and force things through. I have no expectation that I’m going to finish the project that day, so I just chip away in short focused sessions.

Nailed it. My "build" isn't anything near the level of detail as yours but you've summed up what I've been feeling over the past few months quite well.

Enjoyed reading through the posts here and looking forward to the exterior portion of this project.

[proto.corsa]

Fantastic build, interior came out perfect.

[M3Garand]

Nice build

[M3LSB.Gab]

that is one of a build and thread ! can't wait to see the DIY CF roof install and look with CSL front bumper !

[Abrajam]

wow, that things is NUTS

Now that the interior is done, I wanted to share some completed photos and summarize everything in one post. The interior portion of this build has been spread over ten different pages, and I thought it would be useful to have one post that contained everything I’ve been working on for the last two years.

First, the photos
















From the front of the interior to the rear, here’s everything that was done:

• Dinan brushed aluminum pedals.
• Custom / refurbished steering wheel, 1cm thicker diameter, smooth Nappa like leather, ///M colored tri-stitch. Blank upper trim (button delete), lower trim refinished in matte black.
• Steering wheel and dashboard airbags replaced under recall.
• Navigation delete, radio delete panel, new instrument switch panel, HVAC controls moved up, new lower sunglass holder.
• Z4 rear view mirror, manual adjustment with grey clown-nose alarm.
• New sunroof motor cover without home link and sunroof switch.
• New inner door handles without HK logo
• CSL front door panels in matte 1x1 carbon fiber, ceramic coated for a satin finish. CSL door handles in custom brushed aluminum finish. Sound deadening on back of panels. Door panel speakers deleted. Airbags deleted.
• CSL center console in matte 1x1 carbon fiber, ceramic coated for a satin finish. Mirror adjustment switch moved to center console. New hazard switch and mirror switch trim. CSL leather e-brake boot.
• Seat belt assemblies sent off and replaced with ///M colored tri-stitch belts. Factory seat belt tags were re-sewn on.
• Recaro Sportster CS front seats, custom Nappa like leather by AMX performance, ///M logo embossed in headrests, ///M logo tag sewn into side bolster. Seats were installed onto factory seat power sliders with custom seat brackets. Momentary switch was wired for forward and backward movement. New nuts, bolts and bolt covers for seat brackets.
• CSL rear door panels in matte 1x1 carbon fiber, ceramic coated for a satin finish. Sound deadening on back of panels. Door panel speakers deleted. Airbags deleted.
• Rear headrest deleted, headrest holes plugged with BMW blind plug. Rear center seatbelt delete.
• Rear parcel shelf replaced with European version (no LATCH holes), smaller speaker grills without HK logo. Rear deck speakers and subwoofer deleted. New through loading cross member trim. New rear seat belt outlets.
• New c-pillars and interior light bulbs.
• Amplifier, navigation and all other audio components deleted from trunk.
• Massive amount of new clips, screws and fasteners throughout the interior.

Phase 1 of this build complete.

[Avedis]

I’ve been collecting CSL exterior components for the last year or so, but I’ve been putting off paintwork for a couple of reasons. First, I wanted to focus all my attention and money on the interior first. Second, and more importantly, it’s insanely difficult to find a body shop in all of the Southern California area that I trust with this car.


Although I have yet to commit to a particular shop, I recently commited to starting this project. This prompted a whole chain of events: measure, disassemble, test fit, modify, order parts, and eventually, drop off for paint. This process will be documented over many posts moving forward. For the purposes of this thread, this will be considered Phase 2: Exterior Body & Paint.


First, I took measurements of all the panel gaps for the trunk, diffuser, front bumper, rear bumper, etc. This way I had a good reference moving forward on what the gaps were. The goal was to either equal or improve the existing gaps for the new components.





I then took all the CSL components down from storage. Penny (my golden retriever) knew something was up. She doesn’t normally come out to the garage but she wanted to check out what was going on. She was not impressed.




I started with what I thought would be the easiest of the new components, the diffuser. The factory diffuser (and 5 pounds of rocks/dirt) came off easily. The Vorsteiner diffuser got its first test fit. The fitment was 80% there with no modifications at all. The panel gaps were actually even better than the factory piece in most places.




That said, the top of the diffuser refused to sit flush with the bumper. If you look closely you can see it’s sitting about 1mm-2mm proud of the bumper.



There were two minor issues. One was that Vorsteiner made the center alignment tab too wide. It was just wide enough that it wouldn’t push fully into the hole in the factory bumper. This fix was really simple, open up the alignment hole in the bumper, and take a tiny bit of material off the diffuser.




The second issue was that the lip on the top/backside of the diffuser that hooks into the bumper varied in width. It was anywhere between 0.25mm and 2mm too wide compared to the factory piece. This fix was more involved. It required me to take measurements off of the factory piece, score the Vorsteiner diffuser with a micrometer, then use an orbital sander to shave down the lip, matching the dimensions of the factory diffuser.



First the top section.



Afterward it sat perfectly flush and the gap was far better than factory.



Then I moved onto the sides utilizing the same method. Take a little off then test fit. Repeat as necessary.




After those tweaks, fitment was perfect. Here you can see how I checked the alignment of the two pieces. Long story short, if you’re looking for CSL diffuser with zero fitment required, send Gt4 a message.



Next up was removal of the rear bumper.



While the bumper was off, I installed some “Eurostyle” exhaust tips. They are slightly larger diameter and have a more substantial dual wall design that I thought would pair really nicely with the new diffuser. First the factory rivets were drilled out. Then the tips were easily removed.



Here is a side by side comparison/mockup and a full mock up afterwards.





I couldn’t resist cleaning the area before installing the exhaust tips. After a deep cleaning session I measured the tips for perfect alignment, then secured with metal rivets.

[Avedis]

I then repaired the portion of the bumper that supports the bottom middle section of the rear diffuser. It looks like the factory pieces were just plastic welded onto the kevlar bumper bar from the factory. I mixed up some epoxy and resecured the mounts to the kevlar bumper bar. This should be significantly stronger than how the factory did it.




I got into a really nice work groove and was making progress fast. My plan for the day was just to do the exhaust tips and remove the rear bumper, but I did far more than that. I ended up removing the factory trunk and test fitting the genuine CSL trunk lid I had previously purchased from a forum member. You’ll see that it’s already painted, but the paint is in really poor condition and the whole thing will be getting restored. I threw the trunk lid on without making any adjustments from the factory trunk bolt locations. This is exactly why you go genuine on the trunk. It fit 90% perfect with zero adjustment.




I spent the next two hours (literally) learning how the adjustments on the hinges and bolts affected the fitment. I must have opened and closed the trunk 100 times, each time making micro adjustments. I got it really close but there are still some areas I will finalize after paint. I couldn’t resist throwing on the rear bumper and diffuser to see how it all looked.



Things were coming together really nicely and I just had to put everything back on for a quick mockup.



Next I jacked up the front of the car and removed the factory front bumper.


I pushed on the Mile End Composites CSL front bumper. Fitment was near perfect with zero adjustments. I simply pushed it on and snapped some photos of the alignment. One of the things I was pleasantly surprised by was that the factory non-CSL windshield washer fluid reservoir fit within the new CSL bumper. This was a really nice and thoughtful touch by Mile End.

I have some Trinity Graphics front and rear bumper mounts enroute. I will continue to tweak, adjust and document the process. Until then, we’ll leave it here.

[0-60motorsports]

Awesome update. Always look forward to your detailed posts. I need to get those seatbelts done

[bavarian3]

Great update. The replacement tips are genius! Care to share source?

I'm also about to start working on my CSL exterior parts and was wondering how to solve this since the oe tips may look funny. Most of the aftermarket muffler options don't seem to offer an oe-looking straight cut, chrome style. Curious what else you considered.

[Kipjames3]

This makes me feel very good about my recent purchases of a Miles End diffuser and front bumper, and an OEM trunk. Everything looks great so far. I'm always looking forward to updates on this build.

[fattycharged]

Bummer on the Vorsteiner, I saw some photos of a local one to me and it definitely had the same issues


Sent from my iPhone using Tapatalk

[cornerbalanced]

If you need to clear up space and end up selling your front bumper, I’ll take it! Mine has license plate holes.

Car is going to look fantastic once everything is installed.

[Avedis]

Great update. The replacement tips are genius! Care to share source?

I'm also about to start working on my CSL exterior parts and was wondering how to solve this since the oe tips may look funny. Most of the aftermarket muffler options don't seem to offer an oe-looking straight cut, chrome style. Curious what else you considered.

The tips are from a UK seller that mainly caters to the M3Cutters forum guys. They can be found HERE, not cheap, but were exactly the look I was going for, plus predrilled for E46 M3 pattern. If you are considering buying them, I would get them. When he sells out, he is out for literally months before a next batch is available. If you want straight cut single walled exhaust tips with slightly larger diameter, Burkhart Engineering sells sets in 70mm and 76mm.

Exhaust wise, I never really considered anything. I knew that I did not want to change out the muffler itself for anything louder, as I am really enjoying the CSL intake noise.

This makes me feel very good about my recent purchases of a Miles End diffuser and front bumper, and an OEM trunk. Everything looks great so far. I'm always looking forward to updates on this build.

When I purchased the Vorsteiner, it was about a year before GT4 started making his. At the time, it was the best fitting and certainly the best 1x1 weave. It was also the only option that included "the ridge" that separates the carbon from painted section. Now, in 2025, the GT4 is a no brainer. I wasn't too bummed because I'm a weirdo and actually kind of enjoyed making it fit perfect, but most buyers would expect perfection at the $1400 price range.

If you need to clear up space and end up selling your front bumper, I’ll take it! Mine has license plate holes.

Car is going to look fantastic once everything is installed.

I'd definitely consider it, but it would have to be picked up in the Los Angeles area. No time nor motivation to ship this thing.

[Kipjames3]

When I purchased the Vorsteiner, it was a out a year before GT4 started making his. At the time, it was the best fitting and certainly the best 1x1 weave. It was also the only option that included "the ridge" that separates the carbon from painted section. Now, in 2025, the GT4 is a no brainer. I wasn't too bummed because I'm a weirdo and actually kind of enjoyed making it fit perfect, but most buyers would expect perfection at the $1400 price range.

He sent me photos of the diffuser installed and it looked great. I already heard good things about their bumpers so I thought why not grab both. He gave me a little discount also for purchasing them at the same time so couldn't pass that up. I have a Karbonius trunk and SG diffuser and I'm not super happy with the fitment (they were on the cars when I bought it), so I thought I'd just start from scratch with their diffuser and an OEM trunk. Patiently waiting for that to ship out from Schmiedmann but it's saying backordered until the end of May at the moment unfortunately.

[cornerbalanced]

I'd definitely consider it, but it would have to be picked up in the Los Angeles area. No time nor motivation to ship this thing.

Let's do it! I'm by Manhattan beach and work in Torrance - from memory we're pretty close