I don't know what the rules are in Australia, but here in the U.S. we're restricted to 4 door sedan bodies which must be replicas of cars that have actually competed in a touring car race series.
The most popular bodies here are the verious versions of the Stratus, the Protoform and Andy's being the two most popular.
I've done nearly all of my racing with those two bodies. I think the Andy's behaves a bit more aggressively than the Protoform.
I've run the Protoform Vauxhall and Alfa, the Alfa seemed to have more steering than the Stratus, and the Vectra seemed very similar to the Stratus to me.
Trips