I have an 2015 M3 which has a problem with the differential bushing cracking. I took my car to the BMW Dealer several years ago when the car was still under warranty and they couldn't find anything wrong. When I brought my M3 for service they identified the cracked bushing. Although I had to pay for the repair, the car drives significantly better and doesn't make a thumping sound when you let off the throttle. Excellent job as always! Thanks Callas!