Black Mamba 3" (76 mm) Decat Downpipes for Audi RS6 C7 / RS7 C7 4.0 TFSI, constructed from premium T304 stainless steel with precision handmade TIG welds. This 2-piece kit eliminates the OEM catalytic converters, significantly enhancing exhaust flow and delivering an average power gain of 55hp on St..