Fabtech Suspension Systems for Ford F450/F550 4WD also features distributed impact load to the front suspension with strengthened lowered control arm crossmembers. Front differential is protected by a ¼ inch thick steel skid plate that is tightly formed and the rear suspension lift is completed via a block and add a leaf system. These features are only possible through the extensive design job made by Fabtech for truck owners who demands the best in suspension. Fabtech Suspension Systems for Ford F450/F550 4WD are available in two kits. The Basic System features all the components needed for a complete lift and comes with a front coilover spacer system for a stock like ride. While the Performance System offers the same kit parts like their Basic counterpart but this time a choice to upgrade to a Dirt Logic 2.5 or Dirt Logic 4.0 Adjustable Coilover shock that replaces the vehicle's stock shocks is available.