For Audi TT Stainless Steel Turbo Downpipe/Dump Pipe - Quattro Mark 1 Made of high quality T-304 stainless steel with computerized mandrel-bends TIG welded CNC machine flange for strength and durability Maximizing smoothest exhaust airflow Increase engine output and efficiency. Gain 10 - 15 HPs (approximately) O2 Sensor Bungs Insertion, Bolt(s) and Metal Gasket(s) Included