Unsure if original response posted...shocks keep wheels on the ground. Springs support additional sustained loads (pre load). Bilstein 200 lb front and 400 lb rears are forgiving for daily driving but stiffen up on obstacles. I have added 650 additional lbs to my rig w accessories. They (shocks and springs) have different duties, and they work together. TOTALLY worth it if you're gonna venture outside of pavement. Careful on the 700lb springs out there if you're not packing that kinda load as they ARE STIFF for daily driving. Have fun!!