you can put 3" under it do a tiny bit of fenderder trimming and put the stock flares back on ......or trim enough for TJ flares and put those on (it really looks great )... XJs are really weird to lift ...Being Unibody and all ... you can probally expect to spend about $1000 for the first 3 inchs and about 1k for every inch after that for factory kits thats generally the rule of thumb the reason being I guess after 3" you gotta get into an SYE kit blah blah. I belive It is Jeepchick of this forums Fame has 4 inchs into her XJ customly built and is on 32" MTRs And I'm certain if she wanted to should stuff 34x9.5's in . I have 2 inches into mine with coil spacers and add-a leafs in the rear on 30s and Sacked out leafs and no fender trimming ... I can stuff 31 in as it sits, but Me thinks I'm gonna start anew with coils and new leaf packs and stuff some 33 or 34 pizza cutters in ..... there is a guy on with the Calgary Jeep assoc that has the Skyjacker 6' lift and loves it with 35s (I believe he has 35s) ....I have heard of but never seen the new skyjacker 8" lift for xjs ... I believe the price is about $5K CAD (some trimming I suspect you can fit 38.5s under it

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well whatever I have gone off away from topic .... just remember if you decide to trim you must weld the rear back together or all body streath is lost (being a unibody and all)... with 3"s of lift you generally dont need the new control arms blah blah blah you can getaway with stock parts, anymore then yougots to replace everything ....shocks, control arms, steering geomertry etc.......
Hope this helps a little
Mikey