I picked up the e39 M5 calipers and rotors for $250. For new rotors on an M5, bavauto.com sells them for $250 per side. So, I got a good deal on the used ones. I spoke to Dave at zeckhausen.com and he has installed e39 M5 rotors and calipers on an e39 540i. I have cleaned up the calipers and will paint them sometime in the next several weeks. Then I will pick up some SS brakelines and do the front brakes on my car. Hopefully in time for the next track day.