I know a guy who runs a Fiat 500 in a higher-tuned class. It's amazing what he's had to do to it to make it rigid enough to compete in his class. But, yeah, you'll be able to use the Fiesta so long as you don't mind putting a lot more money into it to make it competitive in those higher classes. Which is kind of a… » 1/11/15 12:13pm 1/11/15 12:13pm