OK so iv had a major exhaust leak on my accord ever since i put on headers(4-2-1).yes there the cheap ebay ones,but still havnt cracked so its not that..i smell gas fumes,and it just seems to putt along and when i rev it backfires alot.i have my OEM cat on,could it be the flex tube or were 4-2 Meet?im tired of having a leaking fart sounding car..i want my nice rumble back like when i had my rusted out OEM one.s...any ideas? and tips of keeping the bolts tight?