Agency Power has this new X-Pipe exhaust system available for the Porsche 991 Carrera and Carrera S. Recently, one of our customers got his installed on his Porsche 991 Carrera 3.4L and hit up a local track day at Laguna Seca to shred the course. You can clearly hear how the center muffler really livens up the 3.4L Carrera engine. As tested on our own Project 991 R&D as seen here, the X-Pipe also adds great horsepower and torque gains throughout the RPM range. Check out this awesome video as he laps past other cars. See more Porsche 991 Performance Parts here.