More Information would help like how big your budget is to spend on the xj do you want an older or newer style one? By model I assume you mean trim level, and best trim is personal opinion. What do you consider an expensive for a lift? What size tires do you want to run? Do you mind trimming a bit Daily driver or weekend wheeler?
You could probably get a 97 to 99 in decent shape for a good price around 4000, the 00 and 01 have head problems if they overheat. Sport level is a nice trim level, anything higher classic or limited are nice but more luxurious (not my taste). If you like the older style better I dont know of any years being particularly any better than others.
I like Rough Country, good quality products, very complete packages, good price, great service. There are many other brands aswell Iron Rock is very good to, Rubicon Express but i think there closed now, skyjacker, Budget boost, and bastard packs. A 4.5'' lift is a nice because you could run 31s and not look to funny, yet you have enough room to go to 33s with nothing else needed axcept maybe trimming for more room, and with the addition of coil spacers and lift shackles you could run 35s if desired. if your gonna spend good money i would stay away from add a leaf lifts go full packs. Long arms can alwasy be added for ride quality but cost a bit more.
If you get bigger tires you might want to regear depending on the size. 31s on stock gears are fine, i run 33s on stock with no problems not the fastest but good enough for me, 35s would be a little slow, anything bigger your gonna want a lot more than just new gears.