Agency Power downpipes are designed to improve your turbo charged vehicles performance. Agency Power;s BMW E82 135i downpipes are no exception. These pipes are made from polished 304 stainless steel. They connect to the headers with a 3" diameter opening and V band flange. They have an inside diameter of 2.60". The larger diameter design will improve exhaust flow, keep boost pressure up and provide improved throttle response. This down pipe eliminates the catalytic converters. Each down pipe has 2 oxygen sensor locations. Thick flanges, sturdy hangers and increased flow make these down pipes a must have for all E82 enthusiasts.