First off, welcome to the site. Lots of guys here with info that can give you an informed decision about your potential swap.

Since you probably already have a 4L80E trans, you're halfway there. Just need to get a 6.0 with the PCM and all accessories, an aftermarket wiring harness or original harness reworked, and some other incidentals, and you're home free. The hardest part is the wiring, and that is even not that hard. Any problems along the way can be worked out by the guys here on the forum. They've gone through it before and can give a helping hand where it's needed.