1) '03 Cobra - (if I could find one for $15K)
2) LS2 GTO (I have an '04...but why not?)

3) Low-mileage CTS...love those cars
WRX for $15K = not a car I would buy without A LOT of research...something would HAVE to be wrong with it, or the deal of the century.
But really, I'd take the money, fix my Goat, and mod my '68 C10.
-Swash