The Optional Collector (Titanium), in combination with the Slip-On systems provides even greater power and unburdens weight from the rear, offering better handling. The 911 with the Slip-On system, upgraded with the collector is noticeably more powerful, especially in the middle rev range. When installing Akrapovič aftermarket optional down pipes with sports catalytic converters or without catalytic converters, which are developed for use on closed tracks only, remapping the ECU is mandatory. When installing Akrapovič aftermarket exhaust system that was developed for use on closed tracks, we recommend remapping the ECU in order to prevent potential »check engine light« warning signals. Shown performance data are measured on a car with manual transmission.THIS PRODUCT DOES NOT MEET EMISSION COMPLIANCE REQUIREMENTS FOR STREET OR HIGHWAY USE.