I discovered a slight bend (maybe 2 degrees at midpoint) in the right rear stress bar on my 2008 Z4 Coupe. It's a relatively inexpensive part (about $42.00). Is it recommended to replace both at the same time? Just how dimensionally critical are these bars? They seem to be made of a relatively hard grade of aluminum. Can they be straightened? How critical is it to the rear toe adjustment?
Are you referring to a part in this diagram? (this is for a E85 Z4 3.0i Coupe, prod. date 5/08) http://www.realoem.com/bmw/showparts.do?model=BU33&mospid=49304&btnr=33_1139&hg=33&fg=30 or a part in this diagram? http://www.realoem.com/bmw/showparts.do?model=BU33&mospid=49304&btnr=33_1141&hg=33&fg=45 What I typically see referred to as a stress bar is a bar mounted to the shock towers, to reduce body and shock-tower flex/stress/deflection - it sounds like you are referring to a rear suspension piece, maybe a stabilizer (swaybar) link, part #6 in the 2nd diagram? Or, part #5 in the first diagram?