PFF60-1421 Gearbox Mounting Bush Insert is a two-part kit that acts to stiffen the upper and lower voiding of the OE mount, helping to restore a level of responsiveness expected from a hot hatch. Made using our Yellow 70A durometer material, it provides the perfect balance between compliance and stiffness, giving control and precision without compromising comfort. A small increase in NVH, usually at idle should be expected when stiffening the mounting between the engine/transmission and chassis. The harder the material used, the greater the NVH transmitted. For total drivetrain control, this new insert is the perfect accompaniment to PFF60-1420 Upper Engine Mount Insert and PFF60-1422 Lower Torque Mount