The Perrin Big Tube Up Pipe is for Subaru builders who are using a larger stock location turbo but are limited by the flow rates of a stock sized up pipe. The Big Tube uppipe utilizes 2" ID 304 stainless steel tubing that is CNC mandrel bent and precisely welded to perfection without the need for a flex section. Flanges are all CNC machined from 1/2", 304 stainless steel to prevent warping and port matching is done for the smoothest possible exhaust flow. A new set of 5 studs are included. Go with the Big Tube to remove restriction on your aftermarket turbo setup and make some big power!