what are your plans for tire size and axle combo? what are you trying to build your xj to do? also are you stock right now? i would look at the road blocks guys ran into installing their upgrades before installing yours (don't know your experience level). there is alot of companies that offer good suspension upgrades (T&T customs, rubicon express, iron rock offroad, clayton and others). to go big for cheap is kind of a oxymoron but you could piece together kits. some companies you can buy separate coils, leaf springs and long arm kits( ironman4x4.com) if you are wanting that much lift, then you might as well get a long arm kit. if you search the forums there are alot of guys who post the experiences they've had with the suspension they are using or have used. i had a 6.5" rough country lift. one of my leaf springs broke so i replaced it with iron rock offroad leaf springs and shackles, awesome product and price. from what i've been told by more experienced XJ owners is that 5.5 to maybe 7 is plenty enough (with some fender triming) to do alot. hope this helps.