I went last night too. It was fun to get in and push the M3. The auto-cross was kind of disappointing though. Just enough to give you a taste and then its over. I did like taking it out onto the roads though.
I am seriously impressed with the M3. Have never driven an M before I loved how it reacted to even stupid driver inputs. And when you mash the Loud Pedal, horry chit! I could get used to that feeling.