If you try to lower Super Duty with springs you get trouble, if you heat or cut your springs, even if you use a "lowering" spring you cause alignment issues you just can't correct out! That's why we made DreamBeams! Our exclusive tubular construction is the most accurate lowering beam anywhere. We use thick walled DOM tubing, nested, welded in the fixture giving you full alignment adjustment. The fabricated "I-beam" type parts suffer from "weld creep" as they are welded, which simply means they warp a little. That makes it hard to get consistent finished parts! You only need to remove the factory beams and replace with DreamBeams and you have a 3" drop with the factory coils, full suspension travel and all the goodness that comes with that.
The rear end is done with a tried and true Hanger/Shackle kit. This moves the mounting points of the leaf springs up on the frame providing the lowering needed to match the front! A bolt on 3/5 kit for your SuperDuty, simple installation is a DJM trait.