The Stage 4 system sees the inclusion of the ICON Vehicle Dynamics Ford Super Duty 4-Link kit, which further improves performance by eliminating suspension bind commonly experienced with factory radius arms during articulation. This “freeing up” of the front end and the ability of the 4-Link Kit to maintain positive caster through the range of travel equates to an unparalleled ride quality in all conditions. With the endless hours ICON has spent testing and tuning our suspension components and shocks as a complete package, you can rest assured knowing that you have the best suspension solution on the market.