Killer B Motorsport 4-1 Holy Header Exhaust Manifold w/ V Band Upipe 2002-2014 WRX / 2004-2021 STI

The popular Killer B Motorsport 321 Stainless Steel Holy Header is a great way to increase the exhaust flow due to the smooth bends in the design that will optimize the exhaust flow. This will help maximize the flow potential of your turbocharger which will also reduce the spool time. This is an equal-length design that will produce an aggressive exhaust note while improving the performance and response throughout the entire RPM band.  FEATURES: CAST COLLECTOR: The collector is made of thick-walled cast 347 stainless. This design removes several welds which removes flow disruption for less turbulence. This also allows the collector to be designed as a true high-velocity merge. SHORT EQUAL LENGTH PRIMARIES: Shorter length primaries make for an equal length header which means less header volume and quick spool up.  SYMMETRICAL PRIMARY DESIGN: A similar tube length and bend geometry keeps the pulse velocities high and consistent when compared to equal length headers with different