For Scion tC Stainless Steel Turbo Exhaust Downpipe Made of High Quality T-304 Stainless Steel with Computerized Mandrel-Bends i.e. Maximizing Smoothest Exhaust Airflow TIG Welded CNC Machine Flange for Strength and Durability Increase Engine Output and Efficiency / Gain 10 - 15 HPs Inlet: 2.25"/ Outlet: 2.5" / Piping Diameter: 2.5" / O2 Sensor Bung Insertion, Bolts and Metal Gaskets Included Direct Bolt-On Installation, Requires NO Modification