K-Tec Racing Stainless Steel Turbo Down Pipe is the biggest bore turbo pipe available with its 2.5" bore. It is a stainless pipe that runs from the turbo outlet elbow down to the exhaust downpipe. Due to its bore size it reduces unwanted, power sapping back pressure which allows the turbo to spin up quicker and more efficiently resulting in a good increase in power. Secondhand.