I replaced it with Pentofrost-NF, which seems good for all BMW's. Anyway I let it warm up, gave it a little gas, still nothing. So I parked in a different spot, gave it some more gas, and lo and behold, coolant is spilling from under the car. I shut it off, and I'm waiting to get it towed.

What are the chances that the cylinder head was warped or damaged? This is the first time the car has overheated, and when it did it was shut off within 5 seconds or less.