2 years ago I bought a BMW 323 for my daughter at the local Carmax dealership. few months ago my daughter started complaining about a clunk noise coming from the rear axle on bumpy roads. I brought the car to Carmax to get it fixed since the car was and is still under warranty. They replaced the shocks but the clunk was still there after that. I brought it back again and then they changed the bushings and other parts of the rear suspension but the clunk noise was still there. I brought it back a third time and they changed the springs. I oicked up the car this afternoon and guess what ... still the same clunk noise. I spent 30mns tonight trying to figure out where this noise was coming from and hurray! I found out that it came from the subamp I installed a year or so ago in the left side of the trunk beside the stock amp. It got loose and was jumping on each bump of the road. So Carmax got me an entire new rear suspension under warranty and this noise was just coming from the submap.