There a lot of choices you can get with that budget, but it depends on what you want. Do you want a gas saving car? Sport car? Truck? etc. From your first post I'm guessing a sports car lol
The Mazda RX8 is a good choice, engine revs super duper high, gets good mpg, and looks cool too. However, it is a rotary engine, it needs
HIGH maintenance. Hell at 50k miles it needs major rebuild at Mazda. Rotary engines don't last long, and they never have lasted that long.
The older Mustang is a great cruising car, but I can't see anyone DD'ing that thing. Does it have power steering? Power brakes? A/C? Engine rebuilt? Any major rust?
Don't get a used WRX. Those are turbo'd and not many people are light footed when it comes to those cars. Plus most people don't even have a turbo timer which is very important on a turbo car (especially if they have a lead foot).
Audi is a nice car but GL paying thousands on maintenance fees...
With that money you could buy a late 99 or 00 Cobra mustang. They aren't the supercharged oens but they are still very quick, and they are fast.

plus endless mod capability down the line.
If you want a mpg friendlier car but sporty, a mazdaspeed (3 or 6) is a good car (if you can find one).