you should be able to find an s13 (89-94) for under $2000... look on ebay
http://search.ebay.com/search/search...Sort&catref=C1
yea the ka-turbo is prolly the better idea, you can run anywhere from high 13's to a dead 12.0 depending on the amount of money you've got. one that runs 13's should go for around 3000, if you want to hit 12.0 it will cost around 7500-9000.