Any off the shelf Kit is sure to please!
I'm personally Torn between two brands for when I long arm the XJ..
Iron rock offroad.. For me, the "3 link" kit they offer (its a radius arm setup.. not 3 link) Is Very Stout, It's Been proven in many Northwest Chapter rigs.. The 3 piece crossmember, as-well as 5/16" D.O.M. tube all for about $700 Shipped, Is a Great value!! Ive witness thousands of miles with Zero Issue's from Numerous rigs..
The other option for me is Claytons offroad.. Dont get me wrong, IRO is a Great kit, But Claytons has a Cult like following for a reason.. Tried and true designs, with Premium Quality Grease'able Currie 2.5" johnny joints.. the Pro-3link kit comes with a Truss, and 6 Of the Johny joints.. for $890 shipped.. Or the Double radius system is $950 shipped..
Honestly tho, From rough country, rustys, IRO, Rubicon express, TNT, Full traction, RockKrawler,Claytons, Andys, BDS, etc etc etc.. You wont find a bad deal.. In my opinion!