I'm not that familiar with that extent of a change over, but you need to know that your '93 Sidekick front axles are 22 spline, and the 00 chevy tracker front axles are going to be 26 spline. It's always been recommended that if you're going to go down this route that you get the front from a 96-98 sidekick - since those are 26 spline. Even then you'll need to create hybrid axles, from what I understand.
I would recommend you call Brent at Trail Tough (877-789-8547), the guy knows his stuff about all this, and can give you insight on all the details.
When I did mine, I used an XL7 front. Auto XL7's here have 5.13 gears. It's a straight swap if you don't mind the aluminum diff, and retaining the air actuator.
I had Brent set my XL7 5.13 R&P up though in my steel GV diff I already had. He removed the air actuator for me and installed a different carrier. The only customization I had to do was shave about 1/4" off my driver's side axle and cut a new groove for the c-clip. We used a grinder in the garage. Fit like a glove after that.