new headers new problems

[whiterod]

maybe when you disconnected the h-pipe from the original headers and installed them on the new headers it might have changed the position of the h-pipe which in turn changed the position of the catback. Exhaust is a funny thing, things cannot bend when you install them, so things must move. Around the catback there is very little clearance as it is around the tailpipes that any slight movement will cause it to rub on something and rattle. And the smell that you are smelling is probably the coating on the headers and it will go away soon.