Add MORE POWER to your FA20 Turbocharged Subaru! The factory OEM manifold is designed as a cost-effective component, whereas the Killer B Motorsport Performance Header is designed with the goal of maximizing exhaust gas performance and increasing power. Equal Length Twin Scroll Design improves exhaust gas scavenging, increasing the engine�s ability to make power. Available for the traditional OEM (or OEM style) turbocharger, or Dual External Wastegate version to deliver maximum performance potential.