Perrin 18-21 Subaru STI Cold Air Intake - BlackPSP INT 326BK PERRIN Performance designed this Cold Air Intake System to be a direct replacement of the restrictive factory airbox. PERRIN Performance has developed this intake system to use proper MAF alignment as well as plumbing size to maintain an appropriate air fuel ratio, as well as preventing any check engine lights. This intake system features a smooth aluminum intake pipe that reduces turbulence to promote better airflow throughout the