An aftermarket gas tank skid should be #1 on an XJ. If the tank does not rupture it gets pushed up pinching off the fuel line. The next is rocker skids. If they get hit it interferes with the way the door opens or worse when jams them closed. It's also so a very difficult type of body work to do. Next on my list would be to pick up and carry a few stock axle shafts and the tools to swap them. Put Grand Cherrokee tie rod on it and make sure your steering box stays tight to the unibody. XJ's work great off road but they need lots of mods. Good luck and have fun with it.
New River, Arizona
Congratulations, you've won the award for worst possible person who's posted on Expo.
John E.