I've got a 32 generac that I'm planning on moding the stock exhaust similar to what Machine did with his exhaust. Basically just cutting the ends off, taking out the baffle and caping the ends off and moving the outlet to the middle of the exhaust, instead of it coming out the side. I took it to an exhaust shop and they wanted a hundred bucks to do that...does that seem like a reasonable price? It's also got some surface rust on it that I would like to remove. Is the best way to just sand it off? I wanted to paint it after but it sounds like it's a waste of time to do it.

It takes about an hour, so what ever their hourly rate is, is about what it should cost. Wire brush it and hit it with high temp grill paint a few times a year. Thats about the best you can do.