What you need to do to the rearend....hmmm, lets see. If you have a peg-legger, get a limited slip diff, any brand. If you have the factory G80, switch it out with a new aftermarket LSD, non-govlock. The G80 will eventually break taking the gears with it. I prefer the Auburn LSD but that's just me. Depending which gears you have, you may want to change them. The turbo seems to like numerically low, 3.08, gears over high gears like 4.10s. Depending how you are going to use the truck really helps to decide on the gears chosen.