Invidia N1 Cat Back Exhaust Non ResonatedNOTE: Due to Australian vehicles having different down pipe lengths from MY01 MY07, MY01 MY05 WRX will require extension adaptor INVIDIA N1 CAT BACK EXHAUST Full power. Full flow. Full volume. Blending performance and price, the Invidia N1 Exhaust is a modern interpretation of the classic N1 racing style exhaust. Invidia N1 Exhaust Systems feature cannon style mufflers for maximum flow and minimised back pressure, resulting in significant mid to top