The Slip-On Race system provides even greater power and unburdens weight from the rear, offering better handling. The Slip-On Race system, made of our proprietary titanium, includes side mufflers, a link pipe set with integrated exhaust valves, an X-pipe, and four exquisite tailpipes. Add a Slip-On Race system for even greater power and sound delivery, and the reduction in weight behind the rear axle markedly improves handling. The 911 with the Slip-On Race system is noticeably more powerful, especially in the middle rev range. The performance exhaust system boasts an optional Akrapovic sound kit for exhaust valve control, which offers a choice between a sportier loud sound and regular performance, suitable for everyday driving.