An engine swap is always more expensive than people let on. Especially if you can't do all the work by yourself. The computer from a junk cherokee same year should work as long as it serviceable. BUT the best bet would be to find a donor motor/trans that has the CPU & wiring harness with it all complete. Your linkage is going to be different on the transmission as well, but it may be an easy mod (I really don't know how much different the linkage is).