RockJock's Pro Edition Johnny Joint Suspension System for JL Wrangler Unlimiteds (4-door) with the 392 Hemi engine provides 3 1/2 inches of lift and allows for efficient clearance of up to 37 in. tall tires (with minor trimming, larger tires will require aftermarket fenders). This kit is comprised of only the highest end components in the areas of strength, fit, finish, function, and the engineering to back them. This kit is designed specifically for the serious off-roader who not only wants to lift their vehicle and install big tires, but also wants to tackle the toughest trails in the country with confidence and ease.Included in this kit is the full set of 8 Johnny Joint adjustable control arms, set of 4 progressively wound coil springs including one front and one rear coil spring shim, front (392 specific) and rear bump stop kits, Johnny Joint adjustable front and rear trac bars, 392 specific rear trac bar geometry relocation bracket, front and rear adjustable extended sway bar links and front brake line relocation brackets. For the ultimate off roading package, you'll want to look at all of the upgrade parts that RockJock has to offer that can be added to this kit to finish this build off! Next level offerings such Antirock Sway Bars and Currectlync Heavy Duty Steering are a must for serious off-roading! Shock options to suite this kit are available from all of the top suppliers.