The 2.5" system includes new coil springs, lower link arms, rear add-a leafs and Superide shocks. Standard or Rockrunner lower links are available.... which style is right for you? It depends on your budget, and how the Jeep is used. The XJ / MJ has a uni-body chassis that exhibits quite a bit of flex. In light of this extraordinary chassis flexibility, owners that go four-wheeling frequently will prefer the Rockrunner links, which feature swivel ends for optimum articulation. These premium links also utilize factory type, steel encased rubber eye bushings at the links' upper (uni-body) ends. This combination of rubber upper / Urethane lower bushings transmits less driveline vibration, extends service life and provides quieter, less "squeak prone" operation. The Standard links are a fixed length (non-swivel) design that utilizes less expensive Urethane link-eye bushings on both ends. Use Standard links for a "budget build" and / or if your Jeep rarely sees off-road use.