thx for all the great info. i have 2 cars that are leaking, a 90 integra which is the one why i asked since its going to be my DD soon, it leaks on the welds in the mid section of the piping i think there is even a small leak before the cat and then 2 after teh cat. the welds look really half ass and need to be redone since theyre leakingand the muffler is all messed up too