BMWs although they have a good reputation, are not a very good car in the suspension department. Where do I start, all of the below give alot of trouble ..........
Front ball joints (on your car, the whole arm needs replacing as the balljoint does not come seperate)
Front arm, rear bushes
Front and rear shocks
Rear pivot arm bushes
Rear top shock mountings
Front and rear coil springs
You would need to get it checked out at your local garage to see where the wear is