aFe power introduces an all new Twisted Steel Header for the 2004-2019 Subaru WRX STI with H4-2.5L engine. In testing, this header produced a max gain of +9 horsepower and +13 ft. lbs. of torque verified by our in house dyno. aFe spent countless hours of R&D to develop the perfect balance of pure race-inspired performance. Theses headers are constructed of near equal length mandrel-bent 1-5/8" into 2-1/2" 16-gauge, 304 stainless steel tubing and uses 3/8" thick flanges for strength and to ensure a leak free seal. The smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and durability. To eliminate dead space that can cause turbulence and hinder flow, a 4-to-1 formed collector and optimized tube lengths are used. This combination helps increase exhaust velocity improving flow, as well as horsepower and torque improving throttle response. This system retains factory mounting locations and requires no modification for a simple, hassle-free installation.

TIG-Welded: 
100% TIG-Welded by certified craftsmen for race proven strength and durability. TIG-Welding provides the strongest welds reducing stress cracks.

Retains Factory Sensors:
This system was designed to retain all your factory sensors for a hassle-free installation.

3/8" Laser-Cut Flanges:
These headers come with 3/8" thick laser-cut head flanges and gaskets that are designed to match the head port for a leak-free seal.

Formed Collector:
The 4-to-1 formed collector is used as an efficient way to collect header primary tubes together.

304 SS Construction: 
These headers are constructed of durable CNC mandrel bent brushed 304 stainless steel tubing for maximum performance, corrosion resistance, strength and resistance to cracking

Hassle-Free Installation:
All hardware and brackets are included for a hassle-free installation. This unit also comes with a 2-year warranty.

Also Fits: 2006-2014 Subaru WRX & 2005-2009 Legacy GT with H4-2.5L Engine.

Emissions Disclaimer:
This product is not currently CARB exempt and is not available for purchase in California or for use on any vehicle registered with the California Department of Motor Vehicles.

aFe Power headers are engineered and manufactured in our Corona, California manufacturing facility.

• Constructed of 1-5/8" into 2-1/2" 16-gauge, brushed finish 304 stainless-steel tubing
• Incorporates a 4-to-1 formed collector
• 3/8" Thick laser-cut flanges
• Retains factory sensors
• Optimized near equal tube lengths improve flow and performance
• 100% TIG-Welded by certified craftsmen for race proven strength and durability
• This system produced a max gain of +9 horsepower and +13 lbs. x ft. torque verified by our in-house dyno

Application: