Your polluting turning a Camaro SS with a 6.2 L/376ci motor, I love pulling up next to a Prius with my cutouts open and 22* of catless overlap on a nice HOT azz day in humid shitcago.
L99 has NO cats, the blown GTO has NO cats, and I sleep well and love the fumes.
Op if you want headers and can deal with the CEL light on and the horrible sound when DOD kicks in then just run them. If not just tune it! I tuned mine back in 2010 just 10? Weeks after delivery and I haven't had a problem.