Daystar uses Polyurethane material in it's leveling kits for a reason. It's an insulator. It absorbs the Noise, Vibration, and Harmonics (NVH) that come from the suspension and avoids transmitting them to the passenger compartment. All competitors use steel or aluminum in their Leveling Kits. If you were to take apart any factory suspension, you are going to find rubber, polyurethane, and often both in a typical suspension. These pieces are there for a reason; they absorb the NVH. Sure, steel makes a great hammer, but would you want to ride on it?