Lower control arms because it doesnt shorten the distance your spring has available to dampen bumps. Shorter springs have less travel therefore have to absorb a bump in a smaller amount to distance to keep from bottoming out. Lower control arms keep the spring height and adjust the lower ball joint to a lower position. However i have seen some upper ball joints that are maxed to one side because of this and it causes alignment issues but those are typically on extream bagged set ups
EATIN' FORDS AND TUNDRAS
RIP 2005 VHO ecsb 6.0HO, Comp Cam, Nelson Tune, OBX LT's.