You drive a taxi... So clearly wouldn't expect one to understand the game between modified import car owners & the Victoria Police.
By all means, try doing that and see how far it gets you. I'd bet you'll get upgraded from what would probably be a minor defect - to a fully blown EPA... Which mind you, is well without the powers of the Victoria Police because as the law sits - they only need to base a EPA report on suspicion, not fact, such is the law.
They also do not need a warrant to inspect your car and ensure it complies with the states road laws & requirements at all. That comment couldn't be anymore than plain ignorance.
Pays to know your laws before arguing. It's too late to become aware once you've felt the long dick of the law because you wanted to "stand up for yourself".
You can be as polite as you want and in some cases it will simply get you nowhere irrespective of what you "rights" are.