RockJock's Pro Edition Johnny Joint Suspension System for JK Wrangler Unlimiteds (4-door) provides 4 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, front and rear bump stop kits, Johnny Joint adjustable front and rear trac bars, front and rear trac bar geometry correction bracket kits, front and rear brake line relocation bracket kits, relocation kit for the bottoms of the rear shocks, extended sway bar links and a dropped pitman arm. 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. NOTE: 2012 and newer models will most likely require exhaust modifications to allow for full suspension down travel.