Most cars nowadays are out by 6 KM/H lass at 100KM/H my wife 2011 Auroin is from new I am sure, I was like f every bugger is overtaking me all the time and that never happened in the VY Commodore like that, I think my 2015 Lancer is out by 4km/h at 100KM/H easy.
4X4 are always speeding past me regardless, I don't know why maybe there speedos are set correctly. trucks fly past me and then some don't, I set the speed at 104KM/H and still they are passing me. I would happy sit on 130KM/H in 130KM/H zone if the Law was ok to do so, but I do not want to pay or loose points. because the Laws are insane with exceeding posed speed limit.
I just come back on the QLD Wivenhoe Somerset RD the whole lot is now only 80KM/H it's insane, no one could be so stupid to set such a low stupid speed limit f--- I was pissed off, I could not sit on it all the way for the life of me, boring as bat *poo*, if anyone wanted to drive at that speed one should not have a licence in the first place.