The AEM 22-474 Performance Short Ram Air Intake System has been engineered to be an affordable and easy way to boost the horsepower and torque of your engine. The restrictive factory air filter and air intake housing are replaced with this AEM air intake system which was designed, tuned and dyno-tested to fit specific Subaru Impreza WRX, WRX STI, Subaru Forester Turbo and SAAB 9-2X models. Air enters the system through an oversized AEM Dryflow synthetic washable air filter for outstanding air flow, filtration and performance. The sound your engine makes when accelerating is also modified to a fuller, more aggressive resonance allowing you to hear and feel the horsepower upgrade. The intake tubing is constructed from mandrel-bent aluminum featuring a durable blue powder coated finish. This air intake system was developed to accommodate the engine's factory emissions control devices including the mass airflow sensor.