let me add my .02 and clear up some mis-information
87-90. i would avoid these
french fuel injection =junk. injectors leak externally and start fires. 177hp
pressurized coolant resivoir =junk. problematic at best.
vacuum actuated axle desconnect =kinda junk
peugot ba10 5 speed manual trans = more imported junk
really crappy abs system that has problems if equipped =junk
they do get really good fuel mileage compared to the 91'-up
91'. i would still avoid these
HO engine and chrysler electronics. 190hp. but they had some wiring differences compared to the 92 and newer
1st year of the regular style cooling system
most still have the cad front axle
5 speed is now the good ax-15
92'-96-. good choice as they are now lower in price
as with all 96' and older. they leak water inside from the heater box and fuse box. yes fuse box. floors rust out from the inside from water pooling in the rf floor board and behind the front seats.
solid drivetrain. reliable
96' got the new head with a gasket instead of rtv
97'-98' also good choice
new body style. interior is nicer. drivetrain is the same
5 spd rare in this body
99' very good choice
best power and mileage for the HO engine. has the bigger horseshoe intake manifold. still has the old factory header exhaust manifold.
first year for nv3550 5 speed. they are noisey but heavy duty
00'-01' ok choice
split exhaust manifolds that dont crack. 3 catalytic convertors instead of 1. low pinion tj front axle assembly to clear the front cats.
other stuff
4.0l's leak oil like a mutha. use that to talk the seller down. head gaskets leak oil on the passenger's side. its pretty normal. just use it against the seller. rear main, oil pans, valve covers, oil filter adapters leak also
exhaust manifolds crack, look for the flex section on the end tubes, these are the later ones that dont crack.
all cherokee's came with the aw4 auto trans. they can go 300k miles and more without a rebuild. drain and fill every 3 oil changes. its only 3.5 qts. dont take the pan off. they dont have a filter, just a screen.
either t case is ok. i prefer the 231 though.
avoid all xj's with abs. all abs equipped have dana 35 rear axles and most have issues.
if you buy one with a dana 35 rear, its no biggie. 8.25" chrysler rears are cheap and plentiful. direct swap other than u-bolts.
5speed's have 3.07 gears
auto's have 3.55 or 3.73
4 cyl has 4.10s
frame stiffeners are a good idea. but the uniody is better than others have said. i dont know of 1 that has them, and they are fine after years of wheeling. i would get them if you plan on keeping it for a while.
low lifts and narrower tires are the way to go. more cutting the better. after 4" of lift you will need a sye. also the lift gets alot more $$ after 4" of lift. 33's will fit with bumpstops and
i think that about covers it