i don't think a cammed truck is stock. Corsa sounds like shit with headers and longtubes, even worse with a cam, that is my opinion...MY OPINION. Corsa sounds great on a otherwise stock truck. I've heard more than one corsa setup. The touring and db on a lt/no cat, and one with cammed, lt and no cat. Actually, I am quite certain I heard Brandon's truck cammed with heads with db, unless he had changed it.
The DB was great while stock but nastybad with just headers. My truck had the 22" magnaflow when I added cam and heads, its still too loud.