I really like the Alfa Romeo Spider. I remember that rowdy little roadster that Dustin Hoffman drove in The Graduate. Man that was one bad ass little car. They've had some decent power over the years too (the 1975-78 South Africa model had 150 horsepower!!). And a time proven method for speed is a relatively low horsepower engine in a lightweight chassis (check out the Lotus Elise - 122 bhp in a 1565 lb-car equals a 0-60 time of just 5.6 seconds - and I know many Elises have been clocked hitting 60 in under 5 seconds).
Tragic that production of the Spider ceased in April of 1993. It will be a fondly-remembered classic.