MagnaFlow California Grade CARB Compliant Direct-Fit Catalytic Converter 4481890 helps keep the check engine light off. DIY installation is easy with the proper tools (no cutting or welding required). With features including mandrel-bent tubing to eliminate flow restrictions and stainless steel construction to resist corrosion, you can have confidence in the quality of this catalytic converter. Using state-of-the-art 3D scanning systems in the design process, the MagnaFlow metrology department ensures this new part to fit and function like the original equipment. This direct-fit catalytic converter is designed specifically for the 2000 Audi A8 Quattro and interchanges with OE parts 4D0 254 550 AX and 4D0 254 550 BX, among others. This replacement part is designed to meet or exceed California Air Resource Board requirements, and has undergone additional testing to comply with CARB guidelines to allow for legal use in California and CARB restricted states, for the listed vehicles.