If you are planning on tires over 31 inches tall then you really should get a 4.0L. The 2.5l 4cyl is basicly a short vershion of the 4.0L I6. In fact the 4L inline 6 is based on the 2.5L 4 popper. Bolth will last well over 200k if you take care of them. However the 4 popper will last a bit longer than the inline 6. But the I6 is a good long lived powerfull motor. They really do work very well off road. But with 3+ buck a gallon gas if I bought a TJ as my primary car it would have a 4 popper with a 5 speed.
Better to be "dead and cool" than alive and uncool.
1999, Sport, 4-door, 4L-I6, AW4 auto, np231, 8.25 rear, dana 30 h-p.
BFG T/A KO P235 tires, KC 130w slimline lights, skid-row t-case skid more to come!