It's true, pretty much any brake disc (metallic or "carbon" - not sure about plasticine...) will glow under hard load. Since we're all in a sharing mood:
Road cars can be slightly modified for better brake performance on the track. Change the fluid for a less thermally conductive, "higher boiling" one ("race-spec") and the pads to a compound that won't glaze over (and if necessary, i.e. older cars, vented metal discs that won't warp so easily might be beneficial). The stock calipers will be fine, and you can avoid having to spend lots on carbon discs which will probably have poor low-temp stopping power and require special pads... That, in combination with sensible driving, should more-or-less eliminate brake fade, though I'd be happy to see it in (it's a reason to make sure you take the precautions above in-game.)
The problem of representing brake glow in the game is dependent on the ambient lighting. It annoys me when games show bright crimson-orange glow from disks in broad daylight. True, you would be able to see the glow from very hot disks in daylight, but it would not look so "saturated" in colour. At night, the disks appear deep red, then bright orange, then back to red, and seem to glow for longer, simply because the ambient light level is lower and the glow can be seen more easily, i.e. at lower disk temps. Couple this with the fact that most digital cameras pick up infra-red, to some extent, and the glow should be much more visible on camera than by the naked eye.
Metals do glow blue at higher temperatures, the problem is, they also glow red, yellow etc. at these temperatures, too (due to the curious electronic structure, which graphite shares [in one direction]) such that all states are excited at the higher energy levels, the mixing of which results in the white "colour". Metals should not be compared to plasma (e.g. flames), which can just as easily be pure colours (e.g. yellow, green, blue or anything in between) as not, since the excitation "mechanisms" are not the same. So, violet (having the shortest wavelength, hence highest "energy") represents the highest "temperature" that we can see. Of course, every material is different, so red-hot steel is not the (exact) same temperature as red-hot iron, or red-hot carbon - the first being a "mixture" of the latter two.
Whether a steel can stain blue is dependent on its constituent metals, e.g. Chromium, Nickel and Molybdenum are common. For example, it's the Vanadium in Titanium alloys that cause them to oxidise to that rainbow effect, since there are many oxides of Vanadium, each with their own "state" and, hence, colour. Sometimes the colour is not caused by oxides, but by other compounds. Either way, the colour is caused by absorption, not emission - so the deep blue colour is caused by absorption of yellow light, as a deep blue pigment would.
-------------------------------------------------------------------------
My opinion is that glowing disks and sparks will make it in. "Backfire" probably will, too - though I doubt we'll see the "clean-burn" example as on that Ferrari 360. Skidmarks are a totally different issue (technically, since they're not transient like the others.) I hope the sparks will have rudimentary collision detection - I didn't like that they intruded the cockpit on the SLS in that Nürburgring vid.
