Killer B Motorsport 4-1 Holy Header 2-Bolt Subaru WRX 2002-2014 / STI 2004-2021 | HH-2BOLT

Part #: HH - 2BOLT. The Killer B Motorsport Holy Header is a top - notch exhaust component. It's crafted using advanced CAD software and simulations to boost power in the mid to high RPM range. Its short primaries and single secondary minimize header volume, enabling rapid exhaust gas pressure build - up. The symmetrical 4 - 1 design keeps exhaust velocity high and consistent as RPMs climb, resulting in faster spool - up compared to long primary/double secondary designs. You'll instantly notice better throttle response and the ability to hold more power at higher revs. **Key Features:** - Short Equal Length Primaries: The shortest possible on an equal - length header for quick spool - up. - Symmetrical Primary Design: Ensures high and consistent pulse velocities. - Smooth Mandrel Bends: Provide unrestricted flow with the largest bends for optimal performance. - Thick Walled 321 Stainless Steel: Ideal for high - temperature turbocharged applications, with better strength and toughness than 304 stainless. - High Heat Retention: Reduces heat transfer, increasing turbine efficiency. Can be ceramic - coated or wrapped without warranty issues. - Lightweight: Only 17 pounds compared to the OEM's 25 pounds. - Compatibility: Works with OEM EJ25 Oil Pans and Killer B Motorsport Performance Aluminum Oil Pan, and any 2 - Bolt Up - Pipe. - Made in the USA: With Killer B's quality assurance. - Up - Pipe not included. **Fitment:** - 2002 - 2014 WRX - 2004 - 2015 STI - 2004 - 2014 Forester XT - 2005 - 2009 Legacy GT - 2005 - 2009 Outback XT **Notes:** - 02 - 05 WRX may require a 2.5L STI oil pan. - 06 - 07 WRX needs an STI oil cooler and STI oil pan. - Not legal for sale or use in California on emission - controlled motor vehicles. May need slight modifications to the stock oil cooler for 06 - 07 WRX and Forester XT models, and some models may require changes to the stock fan shroud.

Using the Killer B Motorsport Holy Header is straightforward. First, make sure your vehicle is in the fitment list. Check if you need to make any modifications as noted, like getting an STI oil cooler or pan for specific models. Install the header following the standard installation procedures for exhaust components. When it comes to maintenance, keep an eye on the stainless - steel construction. You can clean it with a mild stainless - steel cleaner to keep it looking good. Since it has high heat retention, avoid touching it right after the engine has been running. And remember, this product isn't legal for use in California on emission - controlled vehicles, so don't use it there. If you want to ceramic - coat or wrap the header, go ahead as it won't void the warranty.