I have one bad rattle in my E90, A pillar driver's side. Sounds like it is close to where the A pillar meets the roof but have not been able to isolate. Frankly the streets are so bad here in New Orleans that I have simply resigned myself to a lifetime of rattles...
2011 Space Grey E90 M3, DCT, Comp. Pkg.
1997 Z3 2.8, Artic Silver, Tanin Red interior, MT
1974 2002tii, Inka, MT