The ARK downpipe and test pipes are designed to get the most performance out of the motor. We use 2.5" Piping SUS-304 Steel. Increases Horsepower And Torque From Mid-Range To Redline. Each downpipe includes a bung hole for O2 sensors and/or CEL Fixers without having to drill into your downpipe. ARK Downpipes with Test Pipe is a direct replacement for your stock downpipe and your secondary catalytic converters. All ARK Downpipe and Test Pipes will bolt directly for OEM Stock Factory Exhaust and/or any aftermarket catback exhaust with OEM fitment only. ARK Advantages and Features: - All Bolt-on System - SUS304 Stainless Steel Construction - Fully Polished Finish, 2.5 inch Dual Piping - CNC Machined Flanges - Includes O2 Bungs - Exposed Micro TIG Welding Items Included: Downpipes, Test Pipes, Bolts, Gaskets, Hardware, Installation Guide *For all orders shipped outside the U.S. tax/duty/custom fees are not included *FOR OFF-ROAD USE ONLY, MAY GET A CEL*