Did the 2 day..totally worth it, and you get A LOT of wheel/track time with some really cool exercises (heel/toeing in the 1M). BMW CCA membership gets you 15% off (used to be 20% in past).
Admin Edit:
Here is a great 2 Day M School journal by another member:
http://www.m3post.com/forums/showthread.php?t=654085