[DaveNP]

Different forces come into play at higher speeds, most obvious being aerodynamics which affects roadholding but also things like rebound speed on the suspension, a road car would be built to behave at 'normal' road speeds not twice normal speed so going there is a gamble. I did some work for VW in the past which included being able to drive cars at high speed on a private track, the Passat had some weird habits above 120mph but the Polo behaved admirably on the occasion I had to emergency stop from over 100mph. But that was also on a private track not a public road where all the other idiots were allowed to bimble along.