Exhaust Catback System Nissan 03-07 350Z Infinity G35 Upgrading vehicle's exhaust system is a great way to build horsepower, free up trapped torque, and improve upon restrictive 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. The net result is lower exhaust backpressure, more horsepower, more torque, and a much better sound