Subaru SF Intake System712100 DESCRIPTION The COBB Tuning SF Intake removes a pre turbo restriction in the stock intake system. The SF Intake intake system utilizes several unique features in an effort to maintain optimal flow for performance while minimizing turbulence that can cause engine management problems. From a custom conical cloth air filter element, a CFD designed velocity stack leads to an unique air flow straightener grid designed to smooth the incoming air flow