Upgrading your car, truck, or SUV's auto exhaust system is a great way to build horsepower, free up trapped torque, and improve upon anemic-sounding factory systems. The larger pipes, low-restriction mufflers, and tuned resonators of a well-designed performance exhaust system can make a world of difference on your vehicle. We have truck and auto exhaust systems from Flowmaster exhaust, Gibson exhaust, and a host of other highly-respected exhaust system manufacturers, with applications ranging from Honda Civic exhaust systems to LS1 Camaro exhaust systems. Those of you with newer vehicles are no doubt thinking, "what about emission control regulations?" The government doesn't take kindly to bypassing smog equipment, something the smart tuner keeps in the back of his or her mind whenever an upgrade is planned. Enter the cat-back exhaust system: For newer vehicles, Flowmaster exhaust, Gibson exhaust, and many of our other premium manufacturers make cat-back exhaust systems (short for catalyst-back exhaust systems) to fit your needs. These cat-back exhaust systems leave the emissions-control gear in place, but allow you to put large-diameter exhaust pipes and low-restriction performance mufflers into the system after the catalytic converter. The net result is lower auto exhaust backpressure, more horsepower, more torque, and a much hotter sound, all while staying perfectly legal.