The first picture shows a ti reflector/duct, they are designed to reflect the heat back at the brake disc, also there is a deflector placed round the outside of the disc to stop heat been transfered to wheel (helps stabalise tyre pressure/temps).
The discs are cooled by air entering the uprights and then directed into the centre of the disc where the vented discs (many variation of vents) give up their heat to the air flow.
The discs have to operate at quite spacific temps again there are many options of material and construction. Too cold = little bit, Too hot and they evaporate very very quickly.

An approx cost is £6000 per axel set. In testing you can use upto 6 axel sets per day per car!

Simon.