PSR Twin Scroll Exhaust Manifold/Headers Heat Coated Ancillary Hose Kits and 1x 1/8” NPT return

and 1x 1/8” NPT return port

That's right

The Big Bore housing allows a 50% larger volume of air in comparison to the Standard Bore housing

and the extended bung length allows only the sensor tip to protrude into the exhaust flow to minimize flow restriction

PSR Twin Scroll Exhaust Manifold/Headers Heat Coated Ancillary Hose Kits and 1x 1/8” NPT returnPSR all stainless steel twin scroll Equal Length exhaust manifolds for New Age WRX STI GDB Type C F. Lost wax finished with 3 1 connectors smooth inner surface for better flow. Stable & effective connection by the slip joint bracket and air leakage avoided by the 3 bolts flange design up pipe. All PSR headers are covered by a limited 1 year warranty.