Jester, that's right - unless it has self levelling and headlight washers because that's what the ADR outlines as being the requirement.
CSP, some after market parts have been ADR tested and complied for the part itself to be fitted in a specific way, like Thule roof pods for example, but most aren't because of the cost of having the testing done, its just not economically viable for the company to do it, sometimes the Government prices itself out of safety. This is where the issue becomes apparent. Then again, there are parts like Altezza lights people can buy from Autobarn which would never meet any ADR to begin with.
Volvo for instance have the worlds safest child seat restraint system fitted to ALL their current cars called "isofix" which uses a rail in the seat base as a firm anchorage point, but they cant use it. So do Subaru, exact same system, but they can use it. Suby paid for the testing to be done in Australia for their cars, and it passed, so they can sell Isofix child seats as a genuine accessory. Volvo can't see the cost of testing being worth while - they wont really sell enough child seats to cover the cost of the ADR compliance, plus make a profit. So they choose NOT to have the testing done, which means they can't sell Isofix child seats.
Its not illegal to sell the part just because it doesnt pass an ADR test, but it can be to fit and thats why so many people come unstuck. Its only an ethical obligation to warn the purchaser the part may be illegal to fit and use, but its not legal binding. You can even ask the bloke at Autobarn or Repco "can I fit it and not have any issues", apart from maybe not knowing he's also not obliged to say anything else and people come unstuck because they think if a large retail store like that can stock it on their shelf then surely its legal.
Steve, what do you think of someone when you pass their car with bright blue window washer nozzles, or red LED parker lights, or undercar neons? They look cool yes, but their not legal. Now I reflect I suppose my comment was a bit harsh, I'll retract it - to me their not idiots, their uneducated modifiers, some of who become quite upset when the police then educate them, and I can dig up some threads from this forum if needed to highlight this point.
Ultimately the owner of the car is responsible for ensuring any modification is still legal, which is why the OP is now asking the question because he's been made aware of the situation that perhaps fitting the DRL's is against the law, could make his car a defect, and should he have an accident may even void his insurance. Sure, the police were also unsure, but I'm pretty sure you'll find if they really delved into it like we are now their judgement would be they are illegal due to the reasons stated, to be a DRL they must deactivate with the headlights switched on.
Ignorance ie "I didn't know" is an excuse, but not a reason when modifying a car, and there's enough resources online now such as this and other forums, to help anyone out. I know at some point in the future someone else will learn from this thread about VZ DRL.