Panel Filter 2008-2019 WRX/STIPSP INT 110 OVERVIEW Dont let a flimsy paper filter get between you and true performance. The PERRIN Panel Filter is the answer. A stealthy approach to higher air flow. Increases in horsepower are a simple easy install away. Quick cleans are simple with our aerosol cleaner and spray oil. After all, more air equals more power! OPEN CELL FOAM ELEMENT PERRIN foam filters are made of reticulated polyurethane foam which offers a minimal amount of air. The