Civic SI (12-15) 3" Header Downpipe

Unleash the potential of your big displacement K motor with our high flowing 3" Header Downpipe.  This product eliminates BOTH OEM catalytic converters.  Available Catless or with a single High Flow Cat!   Features:  3-inch 304 stainless steel piping 3/8" thick flanges Cast stainless steel high flow bellmouth design High quality stainless steel braided flex section with interlock liner Available Catless, or with your choice of High Flow Catalytic Converters Bung for OEM O2 Sensor as well as additional Bung for aftermarket O2 sensor (Plug Provided) Bolts directly to OEM catback exhaust location Dyno: Max Horsepower: 206.88 whp (+20.41 whp gain)Max Torque: 183.74 ft.lbs (+11.24 ft.lbs gain)Note: Number on Dyno Chat is with Metal HFC and 3" CBEWith Metal Core High Flow Cat ONLY, 13-15 whp gainWith Catless version ONLY, 15-18 whp gain