Try calling BMA for good price on parts look for Patrick, they have a website BMAPARTS.COM (I'm not in any way affiliated with them), have good experience with them in terms of parts for my B5 and BMW, but I suggest you call you can get better price that way. Then just look for the DIY link for the brakes here..save you a lot.

 

cost me 400 to take it to a tire/brake center (les schwab) to get new front brake discs and brembo rotors. i think they are ripping you off.