I did the autocross a few years back when the E90 3 Series first launched. It was by appointment only and my "team" included a pro-driver and and two other guys. We started with a brief board session about getting the right lines, proper corner entry and exit etc. We were not competing against other teams, it was more about testing the car at the limits. We did three laps each with the BMW and a lap each in a G35 and A4 for comparison. One of the fellas on my team was an African who only boasting about his M3 and his driving skills. First lap saddess punch the gas turning into a corner and spin out the car, the pro had to grab the steering wheel and pull hand brakes. The man real laugh at him.
Before we left, we did a fast lap with the pro driver and that man had skills. Plenty men out there think they could drive just because they have a heavy right foot, but an autocross track could be a humbling experience.
I recommend this experience to anyone who gets the chance. Cheap fun, no downside other than an urge to go and buy a BMW, but yuh get over that after a few days.