As far as newer cars are concerned, I agree that a Mazdaspeed 3 would be your best choice.

My friend JUST bought one this past week, and he and his wife love it.

Mazda and Nissan are the only companies these days that seem to actually be moving forward with their designs of cars.

Are any Nissans in the ~15k range? A Altima/Maxima would be a great choice.

An older used M3 DOES sound cool, but the only car I see spending 15k+ on that's OLD....is an RX-7 like mine, Supra, etc etc...lol

If I had $15k and wanted a 4-door car, I'd be looking at those 3's.....