The smart car with a Suzuki motor is a pretty neat idea, but if you check out the link to the DP1 I posted earlier its just in another category. The problem with starting with a street car is the fundamental design isn't made for going fast. By starting with my own frame I can design it so that it hardly weighs anything and so that the suspension is optimized for performance driving. If I was going to do it with a street car I think I'd start with something more like a civic coupe, with the availability of aftermarket suspension support for that frame and the low starting weight (sure its heavier than a smart car, but I can make it lose quite a few pounds) it would make a good platform for a rear engine setup. Anyway, to each his own, this type of project is all about doing what you want.