I bought a borla header, and when i installed it i just used the sameO rusted gaskets and when i was up in MN it leaked reallie bad and my car doesn't rumble it sounds like other honda civic, and then i went to the suby dealer in brooklyin park so i can also get 20% off parts, well i took it back to fuji's place, installed it, it still leaks why? well when i got back to WI cheese, i adjust the header gasket(if that is what you call it) well it doesn't leak as much but then it makes a flapping noise from between the borla header and cat converter, it doesn't rumble when i first got it, it does but you hear flapping noise from there, and the new header gasket it seems like it did nothing edit: and when it backfires sometimes it backfires from the muffler and sometimes it backfires from where the leak is, i have borla headers, and stromung catback
dude...you need a custom exhaust...lol...i dunno... with a couple of helpers go under neath the car and try and to feel where its coming from..that'll help a lot.. wagonL