PFF5-4020BLK and PFF5-4021BLK Engine Mount Insert Kits are an intermediate alternative to the BMW Motorsport aluminium inserts and much stiffer full replacement engine mounts available on the aftermarket. Made in our Black 95A durometer material, they are designed to fit the voiding of the OE mounts snuggly to restrict engine movement, perfect for those with tuned track cars. Their design and flexibility also mean they can be fitted to the vehicle without removing the engine mounts themselves. Reducing engine/transmission movement by way of upgraded inserts has the following benefits: – Sharper throttle response – Improved gear shifting – More direct power transfer – More balanced on/off throttle handling – Prolonged life of the OE mounts. A small increase in NVH, usually at idle, should be expected when stiffening the connecting mount between the engine and chassis. The harder the material used, the greater the NVH transmitted. Fits N52, N54, N55 and B58 engines only.