I work in the car industry and here's what I reckon.
1. When you buy a new car, and take it somehwere (pedders/mechanic) and tell them that youve just bought it, most of the time they will pick the shit out of the car. Pedders = $$$$$$$$$$$$$ !
2. I would put money on that car being wound back here or in Japan.
3. Any car you are looking at buying, PAY to get a mechanic you know/trust to check it out first. (if you are on really good terms you may not have to pay) If you just get some random dude mechanic to check it out you never know.
4. RACQ (qld) will find something wrong with any car, they were caught out finding problems with brand new car on some TV show apparently. It is their job to find things wrong with a car. Might be too hard on the car.
5. When dealing with them when you have a drama, stay calm, cool, and don't cause a scene. This will get you a long way, and if it doesn't, just get consumer affairs/fair trading on the phone to them, but dont go making threats straight away.
So basically go No. 3, and get a car with real k's, drive it before you sign the paperwork (with the new wheels on in this instance), and keep control of the situation.