Roush exhaust installed

[Hennyhen]

Wow. The Roush exhaust is 409 stainless steel. This is what I found on stainless works. ", 409 is what is typically used on OEM applications. It has fair corrosion resistance, is magnetic due to the high metallic content, but is a less expensive material than 304. 409 is not an ideal material for a performance/restoration exhaust system because it will turn color (brownish/rust) from being exposed to the atmosphere without ever being run. For OEM’s who never care what the exhaust system looks like, it is a decent material that will last long enough to get past the warranty period. 304 stainless steel has much better corrosion resistance and a lower metallic content than 409. 304 will not turn color from sitting exposed to the atmosphere, and will only discolor slightly from getting extremely hot."