[gtmud]

Options are limited, after 96' they changed the fender area, so unless you want to lift you Xj a couple inches, your about stuck with the smaller tires. Stock rims are 15x7's, i would advise you to look for a set of 15x8's. This way if you plan to lift your XJ you can keep the rims and just change tire size. the largest tire you could SAFELY put on a 15x7 is a 31x10.5R15. They look kind of weird but doable. All this talk about tires, it really depends on what you plan on using this XJ for. Week-end mudder/ dailty driver? Mine is exactly that, when the wife lets me get it muddy, I have 30's(BFG A/T KO's) A great tire, and you would be surprised, just a 2" lift and the trouble, I mean fun you can get into. If you are considering a lift, would strongly suggest the 3" at least, still a lift you can do in your drive way, and it looks nice sitting up a bit.
Good luck.