SUBARU AIRBOX STI 2015-2018715160 DESCRIPTION The SF Air Box adds the benefits of a cold air intake to the outstanding performance of the SF Intake. The factory inlet directs cold air from the front grill to the SF Airbox, which encloses the SF Intake. Hot engine bay air that robs horsepower is prevented from entering the intake system to provide consistent intake performance. This unique design also separates rainwater from the intake air, eliminating the water ingestion