AEM 50-State Legal Performance Air Intake Upgrades for Subaru WRX STi Forester BRZ and More

The 2015 Subaru WRX STI is powered by the EJ257 intercooled and turbocharged H4 boxer engine

The 2015 Subaru WRX STI is powered by the EJ257 intercooled and turbocharged H4 boxer engine.

The VA series 2015 Subaru WRX is the first WRX to move away from the EJ-series engine

The VA series 2015 Subaru WRX is the first WRX to move away from the EJ-series engine replacing it with a 2.0L FA20DIT direct injection boxer engine with a twin-scroll turbocharger.

AEM engineers design our short ram and cold air intake systems as a fully integrated component of the vehicle. Significant testing is performed to assure proper airflow management with the goal of keeping inlet air temperature (IAT) at or near ambient air temperature. AEM intake designers seek to create air intake systems that produce the highest power gains in the RPM range that will most enhance the driving experience. AEM intakes take advantage of several tuning methods to create power gains that are repeatable, safe, and consistent.

AEM street legal cold air intake, number 21-735WB, for 2015 Subaru WRX STI 2.5L models

AEM cold air intake 21-735WB

AEM street legal air intake, number 21-732C, for the 2015 Subaru WRX 2.0

AEM air intake 21-732C

AEM has a solid reputation within Subaru enthusiast communities for creating Subaru short ram and cold air intake systems which boost horsepower and torque for WRX, WRX STI, BRZ, Forester, Impreza RS, Legacy, and Outback models. Additionally, AEM has streamlined its internal processes to make obtaining an Exemption Order (EO) from the California Air Resource Board (CARB) efficient.

Obtaining an EO from CARB makes our air intake systems available for sale and use in California as well as all other states with similar emissions standards. Southern California has one of the densest populations of Subaru fans, and these owners are able to boost performance of their WRX, WRX STI, BRZ, Forester, Impreza RS, Legacy, or Outback without worrying about being hassled at their car’s next smog check.

2008-2017 Subaru Subaru WRX, Impreza WRX, and Forester Models

AEM air intake 21-742C will fit 2014, 2015, 2016, and 2017 Subaru Forester 2.0L H4 engines. Dynamometer tests with a 2014 Subaru Forester showed impressive estimated horsepower gains of around 20 horsepower. This intake includes an AEM Dryflow synthetic air filter with washable filter media.

AEM air intake 21-732C is designed to provide horsepower and torque improvements for 2015-2017 Subaru WRX models with a 2.0-liter H4 engine. This intake kit includes a mandrel-bent aluminum intake tube featuring a durable powder-coated finish. An AEM Dryflow synthetic air filter made with oil-free washable filter media is also included, to replace the restrictive factory air filter.

AEM's 21-735WR and 21-735WB cold air intakes produce horsepower and torque gains by replacing the restrictive factory air filter and intake housing. These intakes feature high-quality aluminum intake tubing with bright red or black finishes, to fit the look of your engine. These intakes are compatible with 2015-2016 Subaru Impreza WRX STI models and 2015-2017 Subaru WRX STI models with a 2.5-liter engine.

The third gen Subaru WRX STI hatchback was released in the United States in March 2008

The third gen Subaru WRX STI hatchback was released in the United States in March 2008.

In 2010 for the 2011 model year, the third generation Subaru WRX STI became available as a four-door sedan

In 2010 for the 2011 model year, the third generation Subaru WRX STI became available as a four-door sedan.

AEM cold air intake 21-478WR is designed to improve the performance of Subaru Impreza WRX, Subaru Impreza WRX STI, Subaru WRX, and Subaru WRX STI models with a 2.5-liter H4 engine. This intake will fit Subaru WRX and Subaru WRX STI models made from 2012-2014, and Subaru Impreza WRX and Subaru Impreza WRX STI models made from 2008-2014.

AEM street legal cold air intake for 2008-2014 Subaru WRX and WRX STI 2.5L models

AEM cold air intake 21-478WR

AEM street legal air intake, number 41-1408DS, for the 2013 and 2014 Subaru BRZ 2.0L H4

AEM air intake 41-1408DS

AEM street legal cold air intake, number 21-477P, for 2004-2007 Subaru WRX STI 2.5L models

AEM cold air intake 21-477P

2013-2016 Subaru BRZ Models

AEM air intake 41-1408DS was designed to increase the performance of 2013-2016 Subaru BRZ models with a 2.0L H4 engine. This intake kit includes a high-flow AEM filter and an embossed heat shield.

The 41-1408DS cold air intake is designed for easy installation, without requiring any special tools. This air intake system is also supported by AEM's Limited Lifetime Warranty.

2002-2007 Subaru WRX, Impreza WRX, and Forester Models

AEM short ram air intakes, numbers 22-474B, 22-474P, and 22-474R, are designed to boost horsepower and torque for 2002-2007 Subaru Impreza WRX 2.5L H4, 2004-2007 Subaru Impreza WRX STI 2.5L H4, and 2004-2005 Subaru Forester Turbo 2.5L H4 models. These intake kits feature mandrel-bent aluminum intake tubing with red, blue, or polished finishes.

AEM's 21-477C and 21-477P cold air intakes are designed to boost horsepower and torque for 2006-2007 Subaru Impreza WRX, 2004-2007 Subaru Impreza WRX STI, and 2004-2005 Subaru Forester Turbo models with a 2.5-liter H4 engine. These intakes include an AEM Dryflow air filter, manufactured with an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration.

AEM cold air intakes, numbers 21-474B, 21-474C, 21-474P, and 21-474R, designed to boost horsepower and torque for 2002, 2003, 2004, and 2005 Subaru Impreza WRX 2.0L models. These cold air intake kits are street legal in all 50 states.

AEM cold air intake, number 21-472P is a 50-state street legal intake kit designed to boost horsepower and torque for 2003 and 2004 Subaru Impreza 2.5L engines, as well as the 2002 Subaru Impreza RS 2.5L. This intake was developed to accommodate the engine's factory emissions control devices, including the IAT sensor.

Subaru Legacy, and Outback Models

AEM cold air intakes, numbers 21-475B, 21-475C, and 21-475P are street legal in all 50 states and designed to boost horsepower and torque for 2005-2006 Subaru Legacy GT and Subaru Outback XT models with a 2.5L engine. These cold air intakes include a heat shield designed to reduce intake air temperature, and an AEM Dryflow air filter featuring washable filter media.


To find an AEM performance upgrade for your Subaru and determine if it’s legal in all 50 states, use the AEM Product Search on AEMintakes.com. AEM products are available for purchase online, or to find an AEM dealer use the Where to Buy link on AEMintakes.com.