I understand the headers and (rotted) exhaust are one piece, so I'd have to take an angle grinder to the pipes to separate them in order to fit new mufflers. I'm thinking of the shorty mufflers, primarily because they're cheap, but I don't really understand how slip ons work in terms of installation. It can't be as easy as literally slipping them on, can it? How do they form an airtight seal with the header pipes? Is there some sort of gasket I need to buy/fab?