The dreaded vibration while accelerating turned out to be a bad u-joint as I suspected. The u-joint attached to the transmission output flange was frozen up which then caused the center support bearing to hammer apart.
For those considering repairing their own driveshafts due to bad u-joints, I just got mine pulled out and it went a lot faster than I thought it would. When I did my E28 it seemed like it was a worse job than the E34. I started at 7:30 PM and put away my tools at 9:00. Of course that's just the first half of the job. Tomorrow I am having new u-joints and a new center support bearing installed on my driveshaft, then over the weekend I will put it all back together. $290 for a 2 u-joint shaft w/ support bearing and $166 for the muffler
Putting in a new exhaust system and oxygen sensor while I am under there.
1992 BMW 535i-sharked
1982 MBZ-300TD Turbo Diesel