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.
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.
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
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.
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.
Year Make Model SubModel Engine Fuel 2004-2014 Subaru Impreza WRX STI H4 2.5L (t) Gas 2006-2014 Subaru Impreza WRX H4 2.5L (t) Gas 2005-2009 Subaru Legacy H4 2.5L (t) Gas 2015-2020 Subaru WRX STI H4 2.5L (t) Gas
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- So very happy with this header
- It took me 1 min to get used to the new awesome sound. Also the old droning from having a 3in exhaust all the way back is gone. The droning and noise from the exhaust dropped almost 20DB in the interior of the car. Now its 67-72Db which is between conversation and traffic noise level, when you get on it you can definitely hear it though. Car is much smoother but you can feel an improvement in the torque. The acceleration has improved quite a bit. I used to do 15.4sec on the 1/4 mile. 13.97 now. Spooling is about the same when you stomp it but it develops way better from there on. The old exhaust is 20lbs heavier, easy. The exhaust end of the header is 2.5in diam. The up pipe is barely 2in. I'm checking if the invidia is closer to this diam. The grimmspeed is not. I think an up pipe with the header end at 2.5 in that tapers to the 1.5-1.7in dia on the turbo end would make it even better. How about it AFE!!