Yeah, scoutinkeith's right, check the axle ratio. I had the 2.5 L with 4.11 gears and 235/75 15's, and it was a dog. With the larger tires, that would greatly effect the driveability. Check out this website for tire comparison:
http://www.1010tires.com/TireSizeCalculator.asp
The 4.11 gears originally came with 205/75 15's, IIRC.
As far as the 2.5 L, it's supposed to be pretty bulletproof and long lasting. Just not a lot of power.