[chanceparker]

OK, a few people have asked for a DIY on this project, so here goes. I didn't take any pictures during the process, but I think I can make it pretty clear.

Step 1: Get an E46 M3 diffuser. I used a Carbon Fiber CSL diffuser, but I also experimented with an OEM diffuser. Either will work just fine.

Step 2: Grind any tabs off of the E46 diffuser. You're going to make a few simply brackets so you don't need them and they don't line-up anyway.

Step 3: Make your center bracket. I used a piece of sheet aluminum that was approximately 7X11. This is a very simple bracket. All you need to do make a simple bend about 3/4 of an inch from the end.

See Picture #1 to get an idea of how bracket works and Picture #2 for a picture of my bracket taken from under the car.

Step 4: Center the diffuser and attach is using ONLY the center bracket. Take a crayon and mark the center of the diffuser and the center of the bumper so you can line them up. Once you have the center mounted, you can trim the outer edges to fit. A Dremel or any small cutting wheel will work fine. TAKE YOUR TIME AND GO SLOW. Don't try to make it a perfect cut the first time. Purposely cut it too big, then slowly narrow it down to fit with successive cuts.

See Pictures #3 and #4 to see how to center your bracket and the areas you need to trim. VERY IMPORTANT. I would not advise trying to match the E90 OEM shape as shown in Picture #5. Let the diffuser run straight across and it will fit much better.

Step 5: Once you have trimmed the diffuser to fit, you have to make the L-shaped brackets that you will use to attach the outer corners. See Pictures #6 and #7 to see how the brackets work.

Step 6: Once you've made your L-brackets, you have to take the diffuser off so you can attach them to it. I used epoxy to attach the brackets to the backside of the diffuser.

Step 7: Once the L-brackets are attached to the diffuser, it's time to attach the diffuser to the bumper at all three points to check fit. FYI, I used the same screws and clips that attach along the bottom of the OEM diffuser to attach to L-brackets to the bumper.

Step 8: Assuming it fits, you're either done or you can take it back off to paint it the color you need. I used auto quality gloss black spray paint, but obviously you have a ton of choices.

If you took your time, you'll end up with something like Picture #8.

Good luck.

[chrisE92]

WOW! that's some awesome work there!

[NiVeDh]

Great work!

[nano10]

nice project