Great write-up, thanks. I have a new E93 that I've been contemplating doing this on and not sure if I should actually do it or not. The highway drone scares me a bit, I must say. Otherwise sounds like something that would be perfect. Keep us posted on your thoughts and impressions.
BTW did you get this done locally and how much did the shop charge you?
2013 M3 Conv | Mineral White/Black | ZPP | M-DCT | EDC | Prem. Sound | 19" 220M | JBSpeed Grilles | IND reflectors | Laser Interceptor