I've got one cool and one hot. I've notice that when I tell my hot driver to pace up he gets to the far right almost twice, if not three times as fast as my cool driver. Also, the farther in the red during the race the more aggressive Bob will be. The cooler is like a "coast" and just going through the motions, they're not trying to set and lap records. So far, my hot driver is a lower level, but I am more happy with the way he is leveling and driving. It also seems like when my hot driver levels up, he is leveling faster (his green bars are getting bigger faster). So, that's my experience so far, hope it helps you guys out. B-spec is really fun for me and I find myself playing it a lot, so any thoughts, hints, or tips are more than welcome. I've got a lot of b-spec experience so anyone with questions hit me up.