Killer B Holy Headers WRX / STI Subaru Turbo Models EJ20/EJ25 2002-2021 | HH4-1 discontinued-with-inventory and where the factory inlet/outlet

and where the factory inlet/outlet locations eliminate the option for a proper N-FLO design

Preload is separate from ride height

Part #: PSR-216BFWBBOSM

Part #: IS-240SR-OCK-GB

Killer B Holy Headers WRX / STI Subaru Turbo Models EJ20/EJ25 2002-2021 | HH4-1 discontinued-with-inventory and where the factory inlet/outletPart #: HH4 1 The Killer B Motorsport Holy Header for the Subaru WRX STI was developed using state of the art CAD software & simulations to determine optimal design to increase power in the mid to high RPM range. Short as possible primaries with a single secondary significantly decrease header volume allowing exhaust gas pressure to build quickly. Symmetrical 4 1 design maintains high and consistent exhaust velocity as RPMs rise. You can expect faster