major cost was the rotor hats (as they are 2 peice) and labour. however, the rotors are basically race rotors. a pair of rotors was $600aud alone, labour and machining was $1100, then there is pads, stainless lines and fluid.
but i have to say, these brakes rock! went for a rather spirited drive through the mountains on the weekend...flogging into every corner out of about 200 and i experienced no brake fade at all. and that was even with street pads!