how did 318i, cl7 or cl9 come under consideration in "sports cars" ... secondly bhai if you are going for a sports car than maintenance and fuel consumption should not be on top of your worry list as they are part of the package ...
if you just want a fast car than look for a clean Starlet with a 4efte and that you should do you good, if you want a head turner than you simply cannot go wrong with a RX-8 ... try to find one with a blown engine (there was one on sale here couple of days back) and get it swapped yourself, it won't be best solution on earth but hey will give you your "i have a need, the need for speed" as well as serve as head turner.