I was pretty shocked and impressed when I had my 1986 Jeep XJ 2 door, I found out that pretty much Jeep had made one Model Per say and had Options IE 2X4, I4, 4X4, I6 I did some upgrades Like Dash, went from Basic gauges to Sport gauges with Tach, temp, oil pressure etc. gauge set and Did not have to change any wiring. I think I had to replace the Oil Dummy light Sending unit and temp sending unit to a Electronic style.
I also found out that you can take a 2X4 Unit and add the front axles, Transfer case, even replace and 2.5L I4 with a 4.0L I6 with no modifications.
I just thought this was something cool I would share, Plus for anyone looking you do not need to find a actual 4X4 unit as long as you can find the misc. parts needed at a local wrecking yard to do the mod.