just so you guys know, right now i am driving my parents' saab 9-5 2.3t. it its pretty fast and the understeer isnt as bad as alot of fwd's, but every thime i drive it i wish i were a manual and rear wheel drive. the horsepower is good enough at 180, but i would like a car with stiffer suspension alot, and would also appreciate a lighter car.
so far my candidates have been:
older subaru wrx (sti if i can find cheap) which is low maintainance, awd, decently powerful, four seats, and upgradable.
2bd gen mazda miata. low mainainance aswell, and super fun, and rwd. but pretty gay, and needs body mods for you not to feel like a fool driving it with turbo and a blow-off valve. also no storage really, but a good commuting car, good fuel economy.
1985-1990 porsche 944. fun, rwd, 4 seats. not quite as reliable, but important parts such as clutch, engine and axles are very durable. most replacement parts that tend to break are only about $30. also, its just an awesome classic car.
nissan 300zx twin turbo. pretty low maintainance, powerfun, upgradeable, but looks lame stock so would probably buy a tuned one someone was selling.