Need a replacement catalytic converter for your 1990 Porsche 911? MagnaFlow offers high-quality catalytic converters engineered for 1990 Porsche 911 sub-models and engine sizes. We combine efficient design and state-of-the-art manufacturing to meet or exceed required emissions standards. Select your 1990 Porsche 911 requirements and state vehicle registration to buy the best 911 catalytic converter online that fits your '90 911 and meets your state’s emissions compliance.