BBK Performance Parts Exhaust X-Pipes for Ford Mustang applications offer unrestrictive, free-flowing and max scavenging exhaust upgrade over stock for improved horsepower, torque and aggressive tone. BBK X-Pipes are made from CNC mandrel-bent tubing for lasting performance and use, and are a direct bolt-on for worry-free installation. X-Pipes are available with catalytic converters for smog legal applications or without catalytic converters for off-road use and max horsepower and torque gain.