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IAG's Power Boosting Favorites for Subaru

Posted by IAG Performance on May 31st 2024

IAG's Power Boosting Favorites for Subaru

One of the many benefits of owning a Subaru is the ability to find extra power under the hood by making a few tweaks. Since Subaru is so versatile and easy to modify, you’ll have no problem finding tons of aftermarket products to soup up your ride, but it could also lead to spending money in the wrong direction. That is, you could end up shelling out a fortune on a product that didn’t quite get you the performance gains you’d hoped for, or worse, it could lead to engine damage. Before you go down the rabbit-hole of a million tuning mods, our team of Subaru specialists would be glad to help out with some tried and tested suggestions. Here at IAG Performance, our specialists are also enthusiasts; we love our Subarus and we have access to all the best parts and equipment that any Subaru die-hard could ever hope for. Based on our years of experience, as well as a consensus of customer feedback, we’ve compiled a list of a few power boosting favorites to upgrade your STI or WRX engine.

COBB Accessport


A great first upgrade for your STI or WRX is the COBB V3 Accessport, which allows you to easily flash your conservative factory Subaru ECU with more aggressive maps. Generally speaking, it’s easy enough to flash an ECU, but not all companies provide a means to edit or uninstall performance altering maps from the engine control module. Some maps can completely block ECU diagnostics, which can cause issues down the road, especially when it comes time to pull codes for service. The Accessport not only allows you to store and flash multiple maps from COBB’s Off The Shelf maps cache, but with the help of a Protuner you can also create custom maps, as well as completely reset your ECU to its original tune with the touch of a button. Additionally, the Accessport has a troubleshooting feature that allows you to perform diagnostic readouts and clear the codes.

Click here to view more options from COBB Tuning-


Whether you’re wanting a bit of early acceleration for auto-cross or top-end power for the highway, the COBB Accessport provides you the ability to toggle between your maps and logs on the fly. Of course, if your particular combination of mods doesn’t fit into one of Cobb’s off the shelf maps in your Accessport, you may want to consider getting a professional tune on a dyno. Either way, the Accessport gives you lots of mapping options to choose from, plus the option to dyno-tune. The Accessport has a multitude of features to help you find power in your Subaru’s engine, including a telemetry system that includes datalogging, performance measuring, live gauge readouts and engine diagnostics. You really can’t go wrong with an Accessport, but if you’re wanting to level up to the next stage, you’ll want to consider an air intake.

IAG has a comprehensive selection of engine management systems and accessories, click here-

Vehicle interior with COBB Accessport

Photo display of COBB Accessport and stage 1 package.


An air intake system can benefit the performance of your engine in a few ways; increased airflow can increase horsepower and torque, improve your fuel economy and make your car sound, well, more badass. We have a few good options for setting up your Subaru with an air intake upgrade from brands such as ETS, Cobb, Perrin, and more. or go for one of COBB’s Stage 1+ Power Packages. The 1+ package will get you an Accessport, an SF Intake System, along with the SF airbox, and the post-MAF hose. Economically, the power package is a pretty good deal and since it was all designed to function together, you won’t have to worry about compatibility issues between the components.

Click here to check out our selection of engine parts, accessories and upgrades for your Subaru-


Alcohol based fuels like E85 can give your engine a significant boost in horsepower, but you wouldn’t want to just make the switch without properly setting up your engine’s fuel delivery system. Our Flex Fuel System Kit has everything you need to make your engine compatible with modern ethanol fuels, including E85. This kit includes high flow fuel rails designed to support more horsepower and is compatible with COBB’s NexGen Flex Fuel Ethanol Sensor Kit. The NexGen Sensor kit measures the ethanol content level of the fuel being pumped into your engine and then sends that data to the ECU to be used in a Flex Fuel calibration. This sensor allows you to use any combination and ratio of 93 octane and E85 fuel, and it even does the calculations for you so that you don’t have to deal with handling or inhaling toxic vapors.

Shop more fuel system upgrades here-

Photo of flex fuel system kit installed on engine.

Photo of COBB V2 turbo inlet hose.


A Turbo Inlet Hose like COBB’s V2 can help to increase horsepower by easing the restriction of air to your turbocharger. Aftermarket inlet hoses are generally wider and are designed to allow for higher airflow. More air to the turbo means your turbo will spool faster, ultimately resulting in improved acceleration and increased throttle response. It’s a big upgrade to Subaru’s OEM pleated inlet that is a common point of failure; not only can it cause turbulence in the intake tract and stress on the engine, but it is a source of air leaks and loss of power. Larger inlets are a must when installing upgraded turbochargers, especially those which feature 3” compressor inlets.

Click here for more air intakes and hoses-


If you’re looking to take your FA20DIT powered 2015+ WRX even further, you might want to consider a J-Pipe. GrimmSpeed’s catted J-Pipe has a smooth 3.5" to 3" transition that matches the OEM turbocharger outlet size and then reduces down to maintain exhaust velocity. What does this mean for your WRX? In short, higher exhaust flow results in more power. Another solid option for turbocharged EJ powered Subarus like the STI or WRX is COBB’s GESi Catted 3in. Downpipe. COBB’s downpipe increases the exhaust flow coming out of the turbo, helping to prevent turbo back-pressure, while also allowing for some pretty significant increases in power. It should also be mentioned that the higher flow is going to make your Subaru sound more aggressive, which is never a bad thing.

Check out our options for performance exhaust components here-

Photo of GrimmSpeed catted J-Pipe.

Photo of COBB 20G Turbo


For those who are committed to maximizing engine performance, a turbo upgrade is a logical next step that promises significant power gains. COBB’s 20g Turbo will boost your Subaru’s top-end power without sacrificing low and mid-range responsiveness. The 20G turbo can generate around 400 horsepower, but remains reliable enough to handle a daily commute.

Click here for turbos and superchargers-


While installing your new turbo or fuel system parts, you’ll definitely want to check out the IAG V3 Top Feed TGV Housings. These housings are an upgraded replacement for the lower part of the Subaru factory intake manifold. The IAG V3 TGV improves airflow by opening up the manifold passage, which inturn, makes more power. Our billet aluminum TGV housings not only add a bit of flair to your engine bay, but they can get you up to 13WHP over stock housings. IAG’s V3 TGV Housings allow for fitment of a larger turbo and inlet, making it a solid choice for a power-boosting upgrade. All this, and it’s still emissions compliant. You can’t go wrong with this mod!

Shop IAG's line of parts and upgrades for your Subaru-

Photo of IAG V3 Top Feed TGV Housings

Photo of Blouch Dominator 1.5XT-R turbo.


Another upgrade worth checking out are the larger turbo offerings from Blouch. Blouch features a variety of turbo upgrade options to reach your power goals, including the Dominator 1.5XT-R. The Dom 1.5XT-R is a favorite among Subaru fans because it mounts directly to the stock up-pipe and fits within the same amount of space as the OEM turbo. The Blouch turbo stands out for its efficient design, consistent ability to reach its rated power, and its competitive price point.

For more turbochargers, click here-

Finding power for your Subaru engine is easy enough, but the trick is to find that balance between performance and reliability. We’re hoping our list of trusty upgrades will get you there, or at least give you some idea of where to start. Of course, if you have any questions or need some advice, IAG Performance has the expertise you need. Feel free to give us a call at 1(410)840-3555 or shoot us an email at

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