Stainless Steel downpipe fits BMW M3 / M4 S55 engine F80, F82 shape cars with 3.0T twin turbo engines. Includes stainless steel heat barrier pre-welded to the downpipe. Includes flanges and mounting hardware for a 100% bolt on fit requiring no modifications at all. Although the downpipe is manufactured to look like there is a Catalytic converter build in, it is supplied catless.