The Invidia WRX Exhaust System is constructed with fully polished SUS 304 stainless steel. The exhaust features CNC machined flanges, robot TIG welded, and computerized mandrel-bent tubing for the straightest possible line and the lease amount of bends. This pipe does not have a resonator in the exhaust making it the straightest least amount of turbulence posible. And giving a very aggressive race sound. Tip Size: 101mm Pipe Size: 76mm