BMW Genuine M Performance Rear Diffuser Black High Gloss Replacement 51192455821. The images are for illustrative purposes only and the product may vary, depending on your vehicle. A striking visual at the rear: The M Performance rear diffuser in black high-gloss is made of premium quality PUR material and perfectly complements the rear design. It creates an even more exclusive appearance – and makes the car’s sporty look even more impressive. Benefits of the M Performance rear diffuser in black high-gloss at a glance. Exclusive, athletically elegant look. Perfectly complements the rear design. Made from high-quality, UV, temperature and water-resistant PUR material. IMPORTANT NOTICE: This product is for installation by trained technicians and not by an end user. Installation must be performed exclusively by a specialist workshop. Your local BMW Centre will be able to assist with installation. 1 M Performance rear diffuser. Black / High gloss. Represented by part number 9 in the diagram. 3′ G20, 3′ G21.