This took roughly an hour for installation and was pretty easy. A big change in both exhaust note and throttle response. The truck roars to life now, but maintains a gentle purr at idle and cruising. Combined with the Airaid CAI this dynamic duo lowered RPMs, increased MPGs (avg +1 MPG so far), and seriously increased driving excitement.
2007 GMC Sierra Crew Cab 5.3
I like Flowmaster exhaust so I bought the American Thunder Series and installed it, I like the idea that you have the option of running it straight out by the bumper or 45 degree angle like stock. It has a real nice deap muscle car tone to it which I really like along with the chrome tips that really look nice that set it off.