BMW G20, G21 M Performance Carbon Rear Diffuser And Gloss Black Valance. This Is A Genuine BMW M Performance Carbon Rear Diffuser Including Gloss Black Valance to Allow Correct Fitment. Includes The Following Parts. 51192455819 - Carbon Rear Diffuser. 51192455856 - High Gloss Black Rear Bumper Trim. A striking visual at the rear: The