BLOX Racing Charge Pipe Kit 2015-2021 Subaru WRX FA20DITBLOX Racings charge pipe kit replaces the factorys restrictive hot side pipe on the 2015 2021 Subaru Impreza WRX. The factory charge pipe actually restricts air flow because of the internal ridges and uneven and narrow bends. This kit has been designed to eliminate these factory flaws and provide increases in air flow and performance. BLOX Racings new charge pipes are CNC machined and mandrel bent aluminum then powder coated for durability and to help