W/O knowing where you are, what you want to do with your xj or anything about your mech skills, tools, BUDGET,etc it's kinda hard to make a decent rec.
There is a lotta info on this board about scratch built everything. If you want to follow butcher's rec- check the post "RE 6130 install".
Another thing, if I read your post right, I would drive the xj that you just got a little while to familiarize yourself with and more importantly make sure that everything functions on the vehicle as it exists now. Pay careful attention to brake pads/shoes, rotors/drums, brake wheel cylinders, front hub bearings, axle u-joints, tie rod ends, transfer case, transmission...these are a few of the things that won't come with a lift kit.