rear end in 1991 RS

i have a 1991 rs and i know its a 10 bolt but can anyone tell me more about it

Non posi, 2.73s if it was an auto or 3.08s if it was a M5. The axles are 28 spline though, you can sell those or upgrade with a SLP take out posi without having to buy new axles.

so your saying that if i went with an auburn posi rear end, i'd have to change axles? also which would be better for the 700-r4 3.42 or 3.73? when you put one of these in do you have to change a gear at the end of the tranny....i heard this somewhere but i can't remember where?

Im not sure about the aburn posi, but if it uses 28 spline axles you'll be able to use it. The earlier (some 89 and anything before) used 26 spline. For your money the 99$ SLP take out posi is the way to go.

With a stock A4 305 tbi I'd run 3.42s. Dont want to get out of the powerband too quickly and lord knows we dont have much to play with lol.

With the auburn you will need new axles. I forget spline but I think they were 28. I would stick to 3.42 if you have to drive on the highway alot.

only 99 for a posi?? thats not too bad

I got the $99 SLP take out posi put in mine along with 3.73 gears. It worked out great but cost $300 to install it. I never changed the speedo gear either so my speedo reads higher than what I am really doing.