Farmtruck makes over 1,000hp just on the engine alone. ANything wll sound badass on that thing.
They sound like flowmasters to me. Whatever baffles they use are metal. THey make the idle sound tough, like a flowmaster, then on the throttle that all changes.
Drone, most exhausts drone (whether it be bothersome level or not) at some given RPM.
Whatever floats you boat is what you should run. I ran flowmasters and swapped to Borla XR-1 mufflers, 3" right to the bumper.