Well, I have been driving the 2000 XJ around from time to time. I have run about 5 tanks of gas through it. Runs and shifts out great. Absolutely ZERO leaks of any kind. I am ready to get started on this. I found a donor 1999 4x4 rig and bought it. Got it .extremely cheap and there is zero body damage and no rust. Inside trashed but who cares. I have already been told I have 2 options. 1) cut out all of the damage on the 2000 model then cut out what is needed for the repairs off of the 1999 model. Or 2) swap the unibody from the 1999 and put it on the 2000 model. I am not a mechanic and I am not a body guy. I know this thing can be fixed. How difficult would it be to just switch the unibodies out.. I appreciate your input. I have attached a few pics. The passenger door panels are still usable. The floor is wrinkled on the damaged side but not all the way across to the console.

 

The body and frame are one piece. A "unibody". You cannot remove the frame and transfer it to another body. Write that red body off. It is not usable for anything other than parts

Your post is a little confusing but what I gather is you have a wrecked vehicle(red) that has a bunch of good mechanical parts. And you have a nice vehicle(white) that has a good rust free body but... bad mechanically? What is wrong with the white one?

Assuming there is something wrong with the white one, you should be able to make one good vehicle with the good parts from the red one replacing the bad parts on the white one.