Need Help Bad on Differentials
If it's a M6 you will have 3.42 gears in it.
If it's an auto, then look in the door for the RPO code GU5 (3.23) Stay away from GU2 as that's a 2.73 rear end.
I believe the drive shafts will mount straight up without modification, but I've never done it myself. Only worked on V8 4th gens.

