trick question? you don't have that much money to spend, then you go civic or corolla... maybe even a nice bicycle.
i think the rx8 is a little too aggressively styled on the bottom-half. otherwise they're fairly close, appearance-wise. the problem with aggressive styling is it tends to date. the original M3 and RX7 - pretty timeless (not a lot of extravagance there).
they probably both handle like monsters. then, i'd probably check the fuel economy. honestly, in that range, i'd just settle for something used and wait for a car that doesn't run on gasoline. but some people are saying that's the problem. i say, we gotta learn one way or the other.