Caterpillar ran catalytic converters from 2002-2007. Then everyone else from 2007 on runs catalytic converter and particulate traps.
Donaldson makes a very free flowing 5" in and out on the same side oval muffler made for turbo engines. It quiets the engine, but lets some of the nice exhaust sound through. Donaldson makes many models of mufflers. Good Luck, TomC