The engine mounts have to be moved back a couple of inches, this will get the 4cyl tranny and t-case in the stock 3.0 location. A buddy of mine did this swap this past March when he built his new trail rig. It was more of a money saving issue, he had both engines and wanted to save money on the dual t-case set-up. The wiring wasn't that difficult, however since you have both Runners I would suggest swapping over the entire harness, it is a little more labor intensive but less frustrating than trying to rework the 3.0 harness.

The swap has worked well, but I am not sure it is for everyone, I would diagnos what is wrong with the 3.0 first before committing to a 22re swap.