[s-cars] Drive shaft differences

[audijim at comcast.net]

I am finding out that there are some differences between S-car drive shafts. I say this because of the DS I removed from my 93 S4 and a spare DS I'm getting from a friend who has choice of DS from a 92/93/94 S-cars. Do all the S-cars have a non-serviceable U joint? Why did Audi do this? I made a DS using the rear shaft from a 5000 TQ and the front shaft from my S-car. The 5000 DS was longer only on the front shaft. I swapped out yokes so I could use the serviceable U joint. I just need to get it balanced. Did the 92' S4 have a serviceable U joint? How about the S6's?

Just curious at this point.

Jim