Originally Posted by alan93rsa

There are better 300 series stainless products for an exhaust system. Type 321 is a much better choice. It is titanium stabilized. As such it is much less prone to inter granular corrosion attack, IGA. Cracks form around the welds and everybody thinks the weld failed. The problem is chrome depletion in the grain boundaries in the heat affected zone, HAZ. The lowered levels of chrome allow the exhaust gas condensate to attack the grain boundaries. The problem is at it's worst for low mileage cars driven short distances. If you always get the car and the exhaust system up to operating temperatures then it isn't as bad.

The muffler on my 93 RSA failed around the outlet welds in 2 seasons. I cut out the welds and did the micro analysis in our lab and sent the report to the manufacturer. After initially telling me my muffler failed due to poor mounting, thus voiding their warranty, I got a new system in the mail.

Sorry for being 'really' off topic.