Rework the ranking of boosts

Reworking what's A - B - S Etc class

Too much time we had a S car that was clearly unperforming, but still got the whole response for an S.

For exemple, a Taipan, doesn't go over 146, slides like a drift car, no acceleration and heavy as a truck. That being a S is unreal. There's a few cars like that that are clearly wrongly classed, even in other classes.

I get that there is a luck factor on what car you get, but you should at least have an S class if you go for S class.

Because when you add up the number of times you have boost that lost their upgrade, the cars that are in the wrong class and the Air 1 landing to refuel on a jerrican with 2 heats on you, there's a bit of a balance problem IMO