Need a replacement catalytic converter for your 2009 BMW Z4? MagnaFlow offers high-quality catalytic converters engineered for 2009 BMW Z4 sub-models and engine sizes. We combine efficient design and state-of-the-art manufacturing to meet or exceed required emissions standards. Select your 2009 BMW Z4 requirements and state vehicle registration to buy the best Z4 catalytic converter online that fits your '09 Z4 and meets your state’s emissions compliance.