Troy it was a sprint event run by msca you enter through the cams website
and no not all cars were registered there is a 2 day event at Winton late april you have to be a member of a car club affiliated with msca
and some regulation may include no gaurds or no slicks there was one open wheeler at p/island so i dont see why you could not run.
great bunch of blokes hope to see you at an event soon
chris