Hmm, I own an 05 325 sport, I've heard a clunking noise from mid/rear whenever I shift hard or push the clutch while backing up fast up a hill (driveway). Always thought it was normal. Troubling. Going to have BMW check it out.
Also, BMW replaced my control arm bushings two times in the past 8 months of having the car. They said they had no idea, perhaps too much "hard breaking". Could this be related?