Upgrading your leveled or lifted SuperDuty to 4 links in place of the stock radius arm will deliver a noticeable increase in the performance of the front suspension by allowing it to properly cycle. Overall, radius arms do not have the ability to properly control the axle from rolling, causing what is known as axle dive that is most prevalent when you hit larger bumps and obstacles. By having an upper and lower arm on each side, it can properly control this caster movement, keeping everything right where it should be.