Having reviewed
this thread over on the 2-series forum, I decided to try some supplemental door seals in the hope they would reduce cabin noise. These are not an official fit for the M2, but my dealer's parts department found them quickly under 228i using the
parts numbers. Total cost was $50, the arrived in about a week, and they took about 30 minutes to install on both sides (20 minutes for the first, and 10 for the second). They dry-fit so you don't need any messy adhesive or to worry about screwing anything up. Fitment is perfect, there's no change in this part of cars relative to the the other 2-series.
Given the low cost and ease of install, the only question is...is it worth it? I think it is. These seals fit in a gap between the cabin and the front fender. Without the seals, there's nothing other than the curvature of the door keeping air and front wheel noise from entering the cabin:
You can actually see light coming from the gap between the hood and the headlight!! The entire area behind the fender is open to the door cavity and
there is no seal.
Here's a post-install picture with approximately the same angle on the same side of the car:
Note that, when the door is shut, the new seal sits just beneath the seal behind the mirror and goes all the way to the bottom of the door where the under-side seal begins. This completes the seal around the door.
I did a simple circuit of driving with some city and some ~85 MPH highway before and after the install. The most dramatic improvement is in reduction of front tire noise. There's some wind noise reduction and negligible engine compartment noise dampening. I recommend the modification if you have defeated ASD (otherwise you'd never hear the tire and wind noises over the ridiculous harmonic generator).
A good install write-up is available here:
http://www.2addicts.com/forums/showp...5&postcount=80. Instead of a ruler, I used a bone tool. Once you get the hang of it, though, your fingers are 90% of the tools you need. The trick is getting the vertical placement right, then it's just a matter of cramming the seal into the gap.