Alex,
I did measure temps on a few track events last year but I've been lazy ever since. I was seeing temps in the high 500's low 600's in the paddock. I am sure they must have soared to over 1000 braking for turn 1 on summit. I think if you can reduce the temps by at least 100 or better 200 with these mods you're doing good. throw in race pads, titanium shims and super duper brake fluids and hope for the best