You could use some steel wool, but I think you'll find it is not shiny stainless. It's the cheapy stainless that gets surface rust. That's why it's painted. You'd be better off cleaning it and repainting it black, or repainting it a metal color like the Bonnies have.
The exhaust is not stainless steel - It would not rust if it was. My dad's 93 chrysler concorde exhaust was stainless steel and had not a hint of rust on it at 183k miles. For the best look sand it down, paint with high-temp paint and replace/chorme the tips.
1998 Seville 4.6 *rip* 2001 Aurora 3.5 *sold* 2002 Maxima currently
"I like it when the red water comes out" - saladfingers
According to Oldsmobile it is stainless steel. There are many different qualities of stainless. They all have iron in them, so they certainly can rust. However, your exhaust should last the life of the car. The rust should just be light rust on the surface, it should not begin to flake or anything like that.
The deal with Corsa is they don't make an official system for the Aurora. Both gens are now out of production. However, the STS system can easily be adapted to the 2nd gen. It can also be adapted to the classic if you go to a good exhaust shop. They have to modify some bits for the classic, but it's not too bad. For the 2nd gen, it's basically exactly the same but slightly shortened. I would expect them to not sell it anymore at some point. They probably have a stockpile of STS systems, but I doubt they'll make more. I think they've equipped only 4 2nd gens with the system.