AI Editing question

How do I edit the AI to make the Slower cars slower and the Faster cars faster?

Cars that are rated 10-20 are only 3-4 seconds slower then cars rated 40-70.


I wanna spread them out a bit more >_>

Easy, make the faster range shorter, such as 55-70 or 50-65. Just because the max is at 70 doesn't mean the cars will be going the max number.