Killer B Holy Header Max EJ Series Flywheels then your factory catted up

then your factory catted up pipe may be the culprit

Calibration

The Stage 1+ Drivetrain Package Includes: Subaru 6-Speed Front Shifter Bushing

Complete your suspension upgrade with an Eibach ANTI-ROLL-KIT

and rear diffusers are essential for maximizing aerodynamic performance

Killer B Holy Header Max EJ Series Flywheels then your factory catted upThe Killer B Motorsport Holy Header VE Max was developed using state of the art CAD software, simulations, and testing, to determine optimal high power and RPM efficiency. I High velocity merge collector into a stepped 2. 5" secondary, the Holy Header VE Max is for very high flow applications. Symmetrical 4 1 design maintains consistent and high velocity exhaust gas flow as RPMs rise.