One problem related to rear suspension has been reported for the 2007 BMW 550. The most recently reported issues are listed below.
I have a 550i with the sport package. Both rear tires wore out the inner 1/4" of tire completely while the outer, and the visible portion of the tread had plenty of depth left (approx 4/32" or more). The right tire was slightly worse and blew out on the highway causing a dangerous situation. The left wear was very close. Alignment is within the BMW specs. However, the rear negative camber specification is just too high, and the rear suspension does not have enough adjustment to remove some of the negative camber. BMW should specify a tighter tolerance for the rear camber on these cars (in particular, those with the sport suspension), and specify less negative camber in the rear. Additionally, there needs to be a way to remove more camber out of the rear tires than the stock suspension adjustments allow.