I'd keep my eyes open for an ITS RX7 - second generation. You can get a good runner for $5K and these cars are proven winners, super reliable and fantastic fun to drive.

Here's a potential ITS 944 on Craigslist that is a pretty nice deal for $2700 but needs some finishing. Has the cage, camber plates and lots of goodies. I was told divorce was in the cards if I bought it for a winter project. I'd finish it up and sell for profit if approved by my 'supervisor'. :-)

http://newjersey.craigslist.org/cto/1988548287.html

(I'm an old ITS guy, don't know much about A, B, C)