Lotus Europa with turbocharged Honda Insight drivetrain:
https://en.wikipedia.org/wiki/Lotus_Europa Notice the curb weight - 1,320 to 1,570 lb - is a good 300-500 lbs less than the Insight, which is about the lightest production car of this century. Replace the fiberglass with carbon fiber, make use of titanium for structural elements, and other modern lightweight materials where possible.