PFF85-440R uses our softest Grey 65A material, specifically designed to minimise NVH transmission. Recommended for unmodified Diesel models or for drivers who want a subtle improvement in driving feel, without compromising comfort. A small increase in NVH, usually at idle, should be expected when stiffening the connecting mount between the drivetrain and chassis. The harder the material used, the greater the NVH transmitted. Reducing engine/trans movement by way of upgraded inserts has the following benefits: Sharper throttle response More accurate gear changes Reduced wheel-hop Improved Traction Prolonged mount life