After buying my 1999 Jeep Cherokee Sport 3DR new, I proceeded to log over 168k miles in it until 2012. No power windows, roof rack or fancy bells or whistles. I just sold it last month. Most of my milage was city/hwy driving. I averaged 17/22 MPG. Not too bad with an air conditioner. The off roading in the snow was as impressive as a Jeep commercial can leagaly put on the TV. My service record shows normal maintenance. I needed to replace the clutch at around 90K and the air conditioner was replaced at 120k. The only real problem was a clutch sensor that kept burnig out 15A fuses in the fuse box. The sensor was replaced and it ran well ever since. I liked it so much I purchsed another Jeep.
My fave with the 1999 Jeep Sport 3DR is the fact that I don't need to get out and lock the hubs like I did so often in my '74 CJ-5. It climbs walls and still cruises uphill at the speed limit.
The 4liter is a good, strong motor. It's a Jeep, not a race car.
Possibly adding some steel to the bumpers and 1/4 panels might make it a little bit tougher vehicle. Banging around trees and parking lots tend to reshape the vehicle exterior too easily. Watch out.