I just had my 88 535i driveshaft out balanced and both u-joints replaced along with center bearing bracket. It was done through Mike at Lakeside Motors (Bmw shop) in Scarborough. He sent the driveshaft out to a shop he trusts & it all came back together nice a smooth. You could go through him or try & see if he'll give your the shop info. His # is 416-267-4641.