Circuit Werks latest 2000-2004 Porsche Boxster Resonated Test Pipes. Fits all 2000-2004 986 Base Models and Boxster S Models. Fits both 2.7L & 3.2L. Will also work on 97-99 Boxsters if you use a 00-04 headers. Tri-Bolt flange bolts directly to your OEM or any aftermarket headers with our supplied hardware and gaskets. The Outlet clamps directly to your OEM "C" Pipes. Both Resonated Test Pipes combined only weighs only 10 lbs. You save about 23 lbs off your stock catalytic converters, plus it'll gain/free up about 4-6 hp depending on your intake, headers, and exhaust setup. All combined even more hp gain. There are 2x o2 Bungs on each side of the pipes for your o2 sensors. This listing is for both left and the right side. Please note that this replaces your factory catalytic converter and might not pass emissions in some states. Also available in Straight Test Pipe version or High Flow Catalytic Converters with 200 cell.