My Tranny and Transfer case are shot

MY tahoe is a 1998 2 door Z71 4x4. It has the 5.7Vortech with the towing package with the 3.72 gears. I love this car and I wont the best parts for it so i can drive it for as long as possible.
I am about to shell out some cash to get my tranny and transfer case re-built. I was wondering if anyone had any recommediations on what i should do in this situation. I would like it to be rebuilt to last with good parts and at the same time do some minor upgrading while i have the whole box open so to speak (maybe a corvette Servo and a Shift Kit) any opinions if that is a good upgrade for this vehicle. I appreciate everyones insight on the issue.

Thanks,
Patrick Ewing