I have rattles too, and I think it's mostly caused by the crappy road condition here. No rattles on smooth roads. Over bumpy roads I can hear what sounds like the rear window vibrating over the rear deck. Will tell the dealer about it and see what they can do.
2009 M3 E93 DCT SG/FR Extended
Winter beater: 2009 M3 E93 DCT with Dunlop SP Winter Sport 3D