Zeta is VE. Aussie's seem to stick with the V chassis moniker for there cars, but to us, it will be known as Zeta.
Zeta uses more steel then aluminum for the suspension components. If you have ever seen the Sigma chassis, you can see the extensive amount of aluminum used in the control arms as well as throughout the body. Zeta will be a moddified chassis using more stamped steel. I dont know if you will be able to swap parts from one to the other. And from what I understand, Zeta will be much more flexable.