e30 m3 would be easy, and hell of quicker than your old one. You could pick up a wrx for around 15. An rx7 is well in your range, but you insurance might be high. 300zx twin turbo? Audi UR Quattro? you can pick up a real nice specimen for not too much.

How about a BMW 850? You can pick up a manual for around 16 off ebay.