Lower Engine Mount Insert PFF73-520 Lower Engine Mount Insert Bush is an easy-to-fit solution designed to fill the voiding of the original rubber mount, helping reduce traction issues by restricting engine/transmission movement. It also provides the added benefit of crisper gear changes and extended life of the OE torque mount by reducing the amount of stress and movement in the rubber endured during acceleration and deceleration. A small increase in NVH, usually at idle, should be expected when stiffening the connecting mount between the engine/transmission and subframe. The harder the material used, the greater the NVH transmitted. PFF73-520