I realize the entire system would not be anodized. But it is possible the muffler would be, although is didn't seem to me. And yes, that do anodize parts of the exhaust system, mostly the tips. I realize it would not likely be the case on the cheaply made car, but I was unsure that is why I asked.

 

So are the non SS HHRs', stainless.. Not sure what grade tho..

The mufflers tho, are only aluminized steel..

 

Yeah, even the old cavalier had a stainless steel exhaust. Most salesmen mention it because its a good selling point for the car, like the timing chain instead of a belt, less maintenance cost. Should last at least twice as long as galvanized.

 

Which is awesome news to me after dealing with a '92 Toyota Corolla that ate mufflers...I had the car 5 years and put 3 mufflers on it, not to mention the other parts of the exhaust I replaced.

 

Yes, the factory systems are stainless. What was actually being referred to by the OP was probably an aluminized system, which is similar to a galvanizing process, but not quite the same as galvanizing is not recommended for things like exhaust which get hot.
(I work with aftermarket diesel exhaust, I have a little knowledge about this)

 

More like aluminum plated..or coated...clad coating

 

Wifes 05 Cobalt is stainless (at 75,000 & 6 years still looks good) & so is my 09 HHR LS.