Its not fast cars that are the problem its drivers. For example
I was comming home on the M1 last Sunday in my Brabus. In the outside lane doing 80 in a line of traffic, overtaking slower cars in the middle lane.
I always leave a gap of at least 20 yards behind the car in front, I go at the same speed but leave a gap.
A black MG ZT tried to bully me to close the gap, after a while he pulled into the middle lane and tried to undertake me. There was a slower car ahead in the middle lane I had a choice either brake and run the risk of him misjudging the space available or speed up and get out of the way.
Had I had a normal car or it was speed limited he would have cut in front of me and may well have caused a large accident
The thing is he put lots of people at risk because I left a gap.
Speed limits on motorways should change depending on the weather and traffic levels. If you have ever been on the M6 North of Preston early in the morning you can go for miles without seeing another car, but you can only drive at 70mph.
Who is that bloke in the middle lane doing 50 at three in the morning