What trail ratings are you following? Trailsoffroad rates Saints John as a moderate 3-4. "Guide to Colorado Backroads & 4-Wheel-Drive Trails, 4th Edition" rates it as difficult, their highest rating. It would be more useful to let us know what trails you would like to run.Do you NEED to lift a 2 door JL for difficult off-roading? I’m talking about the 8, 9, 10 rated trails in Utah and Colorado.
If you truly want to run the hardest trails in CO and Moab you will need a lift. You should also be towing your Jeep out there because odds are you will be towing it back and body damage is also likely.
Honestly, I just rent a Jeep in Moab. They limit what trails you can go on, but you still get a good Moab experience without the stress of "this has to get me home".