I would not recommend anything over a 1" body lift (you could go higher, but there will be increased stress on the bolts, making it a bit dangerous for my taste; others have gone higher, and it is their prerrogative, but that is my pesonal opinion); if you re talking about suspension lift, then 2.5" is ussually the highest you can go before having to do other mods (although every Jeep is different, and sometimes even 2.5" of lift may cause some vibes).