Flowmaster Exhaust - 2004 Pontiac GTO 5.7L 2.50" Outlets, Cat-back System - Dual Rear Exit - American Thunder - Moderate Sound For the person who wants the look of a traditional dual exhaust system with all the benefits that a Flowmaster cat-back exhaust system provides. D.O.R. (Dual Out Rear) systems are the perfect choice. American Thunder systems deliver a moderate to aggressive interior and exterior tone and are suited to the enthusiast who wants their perfomance to be heard. Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. Designed for an easy fit, these systems include all necessary parts and hardware for easy installation. •Mandrel Bent 16ga Aluminized Tubing •Moderate Exterior Exhaust Tone •Incl Hangers and Hardware For Easy Installation •Connects After Factory Catalytic Converter •Dyno Tuned for Maximum Performance