Solid engine mounts are a smart upgrade to any track or aggressive street car, and were installed on Porsche factory race cars. Stock mounts are made of compliant rubber, and contribute to imprecise shifting and inferior throttle response. Solid mounts create slightly more interior vibration than rubber mounts, but securely connect the engine and transmission assembly to the car 's unibody, creating a crisper throttle response and shifter feel. Rennline 's solid mounts are cnc machined from 6061 aluminum for strength and light weight, and come as a pair with new grade 8 mounting hardware. Sold as a set of (2)