Problem is, my best driver is "hot headed", but even in a 2J, he can still finish in 3rd place, because he cools down when nothing happens, thus slowing down every single lap.
And a "cold headed" one will probably be as slow. In higher levels (level 40), they rarely make mistakes, if any, but the cold/hot level will go up in traffic and down when leading or trailing by more than "x" number of car length.
If my driver would stay hot, he would never need any imput from me.