Killer B Motorsport 4-1 Holy Header 2-Bolt Subaru WRX 2002-2014 / STI 2004-2021 | HH-2BOLT vendor_HT Autos Compatible with the factory shift

Compatible with the factory shift knob or any aftermarket knobs designed to replace the factory unit

engineered specifically for the upgraded core

Subaru OEM Stock Size Piston Ring Set

That means that the good old 04-05 bushings won't fit

Professional engine assembly recommended

Killer B Motorsport 4-1 Holy Header 2-Bolt Subaru WRX 2002-2014 / STI 2004-2021 | HH-2BOLT vendor_HT Autos Compatible with the factory shiftPart #: HH 2BOLT The Killer B Motorsport Holy Header 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 spool up time