So from the pictures, despite the weight you're stopping, the brakes are not working hard. If they were, you'd see a thick layer of iron oxide around the outer edge, like this:



These pics were after the first track weekend at CMP. The front brakes did not make the full four sessions on Saturday because the stability controls were working over time for about 1/3 of the track. On day two I turned them off and did not have anymore issues, but it was pretty clear the rotors got extremely hot. This doesn't happen on the street. It's just not possible to get brakes this hot on a small vehicle (<8,000 lbs) unless you are going down a steep grade and riding the brakes. Tractor-trailers are a whole different story - the heavily corroded appearance is common for them.