2005 Dodge Neon SRT-4 4dr Sedan (2.4L 4cyl Turbo 5M)
Excellent power, serious fun to drive. You can't find anything better than this unless you spend $10k more and move up to the $30k range to get a Evo or STI. I simply can't think of a car under $30k that can beat the performance of SRT-4. If you are tight on cash and want serious performance, this is your choice. If you are loaded and don't want to park your M3 around the train station every morning, SRT-4 is the only car that you can enjoy driving (and the thrill) and won't feel too bad to find a scratch on it after you return from work.
The peformance, no need to think about after market upgrades for a while. The opportunity to raise the power bar and still keep the factory warranty (stage 1, 2 & 3 upgrades).
Get rid of the spoiler! (or replace with a functional but smaller one).