Ok, I have only had my car for a couple of days (and yesterday I was out of the country) so I haven't fully explored but this is what I have found so far:
2011 E90 Saloon + Navigation Professional + USB audio
After some playing with the idrive (again v new to it) I managed to play over bluetooth with no art work with track position steering wheel controls worked fine.
USB audio (no Y cable, just apple cable on iphone 4):
Played with artwork however it seemed to do something funny with the playlists (ie ignore them) and again steering controls worked.
I will update when I get a chance but I have only spent about 30 minutes in the car so far.