no, Calais have projector lights but they run a halogen globe - I don't think any Holden pre VE has Xenon/HID even the stato's/caprices.
To answer your question
yes, there's heaps of aftermarket kits on ebay you just need to buy the one that replaces the same globe that's in the headlight, which I cant remember what it is ATM. The owners book tells you.
yes, it will be illegal. Any car in Australia MUST by law have high pressure washer and be self levelling. Washer is to stop the light scattering incorrectly from the lens due to road grime build up, and the self levelling is so that the lights don't dazzle oncoming drivers by being shone too high - for instance when you have people in the back or a trailer connected, and the back of the cars down and the fronts up.
That said, because the light assembly is projector and designed for Xenon you'd have to find a prick of a cop or inspector to pick up on it, as it looks like their supposed to be Xenon. As long as the colour is reasonable (ie not too blue) you probably wont be picked up on it at all, I know a few people running round with them that haven't been done.