If you do not have an exemption and driving on your Ps with a GTR. You're not covered.
As to vicroads, you are driving the car illegally. The insurance may allow you to drive it, but once you crash or claim something, they'll find every reason not to accept your claim.
I could insure a lambo under my name on red Ps and they'll still accept my payment. I signed to have the car covered as long as the car is been driven legally.