Alfa Romeo 4C (2013 On)Lower Engine Mount Bush InsertInsert for the original bush. If fitting this to a diesel engined vehicle, an increase in noise and vibration is to be expected. This should be considered as a performance upgrade, not a standard replacement. Our polyurethane insert kit ships with a bolt spacing sleeve made using our Shore A 95 Black material to take up the excessive tolerance on the bore of the original mount to further reduce engine movement under load. Bush Size: OEM Part Numbers: 50521924, 50521925, Quantity: 1 Bush(es) / Required per Car = 1 Bush(es)Road Series Part Number = PF1-1020Black Series Part Number = PF1-1020BLKRoad EAN Reference Number: 5055676540638, Black EAN Reference Number: 5055676540645Diagram Reference = 20NOTES:-See above pictures and car diagrams as applicable.Road Series - For Road and fast Road use. Improve your cars’ road holding and chassis performance by controlling the amount of unwanted flex in the suspension. They offer Prolonged tyre life, Improved performance, Increased safety, Greater cost-effectiveness.Black Series- For Track and Motorsport use. Manufactured using Black 95 Shore A compound to provide maximum control of chassis geometry. They are designed for the Track, ready to Race and are engineered to be the best.Fitting Instructions: Road Series - Black Series