By law your tyres must be rated to do a sustained speed equal to your car's top speed, regardless of whether that speed is legal or not.
I'd get that stuff right, as cops check that data when considering whether to defect your tyres as roadworthy or not.
What a load of rubbish.
The only legal requirements for tyre fitting are that the speed rating of Australian passenger cars be rated S or better and that the load index of the tyres meet or exceed the manufactures spec found on the tyre placard in the drivers door. There are other rules like tyre cannot ride outside of the body etc but basically if you meet or exceed the placard you are good to go.