wait for it,
the answer to this p plater problem is not in the weight, but in the power. i cannot be bothered heading to vicroads site to find quotes or such to back this up, but those who live in fear of these laws will know exactly what it is that i speak of.
in order to be able to drive a hpv on your p plates with out heading through loop holes such as the only car method, you simply have to lower the power to stock weight ratio through modification, this needs to be tested and vicroads needs to be informed of this. i do not know if simple down tuning can resolve this, you may need to question that further with vic police and such, but this does work with the removal of forced induction, i have also heard that this works with certain fuel efficiency mods although i do not know what they are and that is unconfirmed.
hopefully that helps.
now watch as some righteous fool absolutely flames me