The Turbosmart Kompact EM-Series (Electro-Mechanical) Plumb Back Blow Off Valve utilizes a new electro-mechanical function to relieve boost in your new WRX. The Kompact series carries a smaller profile that has been engineered using the latest in blow-off valve technology. The result is a faster responding valve that purges boost quickly between shifts to keep the turbo spooling for improved overall performance.