You know when installing these kind of 2 piece headers... I kno u need a gasket connecting the header to the engine but what about the header connecting to the down pipe and then the down pipe connecting the the cat? Do you need a gasket between the header and the down pipe and from the down pipe to the header??? By the way i have a DC 4-2-1 for a 90 accord ex. I bought it used so it doesnt come with any gaskets.