Go with the Miata as Red suggested. The handling is already awesome in it stock form so with some engine work (Hmmm, S/C doesn't sound bad at all. Never came across such a miata) you already could have a fast car. Again i'll refer to Ben's site about his trips to the Nurbürgring where he raced the first years with a miata. Read his trip reports and you'll know that this car is fast, even stock.
http://www.nurburgring.org.uk/
Good luck with the project.
