fuel economy depends on the drive you get:
FWD up to 30
FDI up to 26
FDII up to 23
There are two lifts available a coil lift from "stu" in austrailia, and a spacer lift from RRO. coil will give you an inch, and stronger springs, spacer is just a spacer and gives about 2". The absolute largest tire you can fit before major suspension mods is 30x9.5 AFTER LIFT. I rand 245/65-17's and I had literally millimeters before rubbing against the strut towers. before lift is 225/65-17 (or its 16 and 15" rim equivalents.)
FDI and FDII are the 4x4 systesm Freedom Drive one gives you an awd system with the ability to lock the system in a 50/50 power split front/rear up to 35mph. It has the benefits of not always having to wait on a slip to engage power to the rear, if you floor it, or are turning hard it will also send power to the rear.
Freedom drive 2 has the same set up but from the factory has tow hooks, skid plates, oil cooler, better seals around doors and such. as well as higher vent tubs for the diffs and stuff. Also it has a lower final drive ratio (hence the lower mpgs) for more of a crawl ratio, hill decent control, and a more aggressive brake lock differential programming when off road.
1989 Cherokee Pioneer
http://goo.gl/OspLWH - amazon link