Keep the check engine light off with MagnaFlow California Grade CARB Compliant Direct-Fit Catalytic Converter 452297. 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. Designed to fit the 2004-2005 BMW 530i and 2004-2005 BMW 525i, this direct-fit catalytic converter also interchanges with OE part 18 40 7 523 903. The included gaskets & hardware reduce the possibility of a leaking seal while avoiding the need to reuse corroded factory parts for installation. 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.