Hey thanks for posting the information. I have a 2001 X5 with only 52K miles and its been a headache so far. I have already had some issues. The latest "self level-error" which cost me about $300 just to have the dealer run test and finally find a blown fuse. Mind you no fault codes ever came, and I am not quite sure if the car is still fixed, since it seems like it has dropped a bit.

As far as Whistling noise, I hear it on my X5 as well, it seems like its coming from underneath, however, can't be too sure. I have read other threads on vairous BMW forum, it appears to be a common problem.