AEM's Performance Cold Air Intake Systems are designed, tuned and dyno-tested to give your engine more power and acceleration by replacing the restrictive factory air filter, air intake tubing and air box assembly.

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The AEM 21-478WR Performance Cold Air Intake System produces horsepower and torque gains by replacing your vehicle's restrictive factory air filter and air intake housing. This air intake system was designed, tuned and dyno-tested to fit specific Subaru WRX, WRX STI, Impreza WRX and Impreza WRX STI models. Air enters the system through an oversized AEM Dryflow synthetic washable air filter for outstanding air flow, filtration and performance. The air filter is located in the original air box space and is protected by a heat shield which is designed to reduce intake air temperature and increase horsepower. The intake tubing is constructed from mandrel-bent aluminum featuring a durable textured red powder coated finish. This air intake system was developed to accommodate the engine's factory emissions control devices including the mass air flow sensor. The cylinder shaped AEM Dryflow air filter is made from an oil-free, synthetic filter media that can be used for up to 100,000 miles before cleaning is needed (depending on driving conditions). The air intake system is easy to install with commonly available tools.

• Precision-tuned and dyno-validated to enhance throttle response, sharpen acceleration, and improve overall engine efficiency, helping maximize horsepower and drivability.
• Creates a deeper, more aggressive induction tone that highlights the intake system’s improved airflow.
• Features low-restriction intake tubing that increases air velocity and high-volume airflow for maximum performance gains.
• Equipped with a long-life, high-capacity air filter capable of up to 100,000 miles before servicing (depending on driving conditions), reducing maintenance while maintaining strong, clean airflow.
• Utilizes washable, reusable, oil-free synthetic filter media that preserves airflow efficiency, traps harmful contaminants, and provides long-term value over disposable filters.

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Application Summary:

Year	Make/Model
2008-2014	Subaru Impreza
2012-2014	Subaru WRX
2013-2014	Subaru WRX STI