Active Autowerke S63 N63 Catted Downpipes | V8 BMW X5 M and X6 M X5 X6 550i 650iActive Autowerke is proud to bring you our hand made Signature S63 N63 Downpipes for the twin turbo V8 BMW X5M, X6M, 550i, 650i, X5, X6 models. Please note that G body vehicles with the N63B engine will need a different version of the downpipe if you are buying a downpipe that also fits the F body cars, it will not fit your vehicle Active is always doing R&D to ensure that you get a product with the proper fit. A turbo impeller wheel speed is mostly