[240racer]

Isn't it possible to have a complete roll cage in those race cars? If so, then you just use that to get all the stiffness you need. The body is just a body, hatch or coupe. The hatch is more sporty, some might say and that's why they went with it. It is also probably more aerodynamic. Also, there aren't any s14 hatchbacks, so there's only going to be s14 coupe ITA cars. If I had a race car of that caliber, the body would be as few of peices of fiberglas as possible and the structure would just be tube frame. I don't know if that is legal in all those classes, but I'm sure you can get really close by bending rules and such.