A couple of pics from cars entered in a race held at the Goodwood Festival of Speed a few years ago. Note that the cars in those races had to negotiate a slalom portion of the course, as a pack, at speed. That explains the side rails (to prevent wheels interlocking, the wheel spats might be a rule requirement too, to reduced wheel to wheel unpleasantness) and the sophisticated suspension and steering. Also their rules dictated a minimum car height. Click on image for full size.