the most popular YJ's are the 91-95 with the 4.0L I-6... puts out about 180HP. 87-90 4.2L are also popular cause they are great for low end torque. then there is the infamous 2.5L 4 banger which i have. from 87-91 they had 105HP, but after that they had abot 125HP, slightly more than the earlier 4.2Lcarb models, which had around 115HP. If you want to run big tires, and speed is an issue like highway driving, id stay away from the 2.5L cause you'll just get disappointed in the end cause you lose power. I have 30x9 BFG ATs with the 4 banger and some air system modifications, filters etc. and it is fine on the highway ad my acceleration isnt that bad. i usually cruise at about 75MPH doing about 2900RPMs on the tach. ive had it up in the high 90MPH range downhill but thats not too safe. The transmission on the 4.0L, AX-15 (from what ive heard) lasts longr than the peugot on the 4.2L, and the AX-5 on the 2.5L. some also prefer the older style YJ roll bar. looking back, all i could afford was my 4 banger at the time, i wish i saved up and got the 6. other than rust, accidents, very high miles 130K+, and YJ should do the trick once you know which engine you want. hope this helps!
95 YJ, 31 x 12.5 ProComp ATs / AR767 wheels, stock 4.10s, 2 1/2" Rough Country Suspension Lift, and huge rusty basketball sized drain holes.