GTA SS mufflers can rust through???

I've heard many people on several forums complain of FlowMasters rusting out, although I bought mine used, and have had them over a year now with no issues.

I think it has to do how you treat them. When you clean your car, don't spray the hose into the mufflers. When you clean the tips, rinse them off with the hose from the side to get minimal water in them. I'm sure water sitting inside anything metal for extended periods of time will cause anything to rust.

400 series "stainless steel" can and will develop surface rust at least, if not rust through under the right circumstances. Even 300 series SS can be eaten through under certain conditions. The 300 series has much more nickel content and thus is less likely to corrode but is much more expensive as well. If you want a virtual rust free material, look to monel or inconel, however, you can also look to pay 10 times more for it.