i have an 04 M6 with 20K. Ive read the post about growling/clunking noise, but this is more of a squeaking noise. I hear it when usually when the car is warm. The noise mostly happens when the tach is from 2600-3000. It also happens sometimes when press the clutch to shift. It is definately a squeaking sound, and i am pretty sure it is comming from the rear. Could it be a differential issue or driveline slack? Has anyone experienced this before?