Killer B Motorsports

Killer B Twin Scroll Stainless Header | 2015+ Subaru WRX FA20 (FAWRTSH)

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Twin Scroll Stainless Steel Header for 2015+ Subaru WRX FA20 by Killer B

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.

321 Stainless Steel offers benefits over common 304 Stainless Steel. 321 is made with the alloying element Titanium. This increases the material cost significantly, but for a turbocharged application, offers advantages over 304. 321 offers Increased Strength and Toughness at elevated temperatures, making it less likely to fatigue and crack. 321 was developed by the aircraft industry specifically to address longevity issues with pressurized turbocharged manifolds; addressing cracking from lower quality grades of stainless steel like 304. 321 Stainless Steel conducts less heat that 304 Stainless Steel. This means a 321 header will deliver more thermal energy to the turbocharger, improving Responsiveness and Efficiency.

Large Radius Free Flowing Mandrel Formed Bends Maximize Flow potential. Common 1D bends are easy to come by, inexpensive and provide the least performance. Advanced Design, Simulation, and Testing was used to verify maximum performance capability of our header. Quality and Craftsmanship come in ½” Thick Billet Precision CNC machined flanges for exceptional Durability and ground flat for Leak-Free Service. TIG welded to Aircraft Quality Standards and Ground Smooth to assure smooth Turbulent-Free Gas Flow.


Backordered. Approximately an 8-10 week leadtime.


  • 2015+ Subaru WRX FA20


  • 321 Stainless Steel Construction
  • Cast Collectors w/ True High Velocity Merge
  • Large Radius Free Flowing Mandrel Bends
  • Adds More Power to your FA20 WRX
  • Quality Materials and Craftsmanship
  • 100% Made in the USA

What's In The Box?

  • 1 - Twin Scroll Stainless Header



Killer B Manufacturer's Warranty

Customer Reviews

Based on 2 reviews
Killer B Headers

Headers fit and finish is perfect, I only wish it came with gaskets for install or was clearly stated they were not included. I impulse bought and then ran around town collecting Grimmspeed gaskets to get everything assembled. Excited to get these on the car with everything else.

Killer B FTW

Got these headers and immediately noticed how great quality worksmanship was put into these. Although I ran into boost creep issues due to the fact that I was on a catless downpipe so If I had to do it again I would've went with ewg headers but nevertheless I knew what I was getting into buying these headers. The sound of these paired with an invidia race cutback and a cat less downpipe was something ive never heard before (in a good way) spooling everywhere I went. Fitment was excellent and very easy to install if you know what you're doing.