I had a vibration due to the rear u-joint (diff end) on my 325e - 215k miles, I took the shaft into a local shop and had a generic joint fitted in for about $150 It worked without a rebalance but I may have been lucky.(nothing to lose though) If you think about it, since the joints are at the end of the shaft its less likely to cause a balance problem. I did give mine the 110 mph test. I recommend a rebalance if the shop can do it.. in my case they would of had to machine a plate to fit my shaft (extra $) so I decided to try it on the car first.