I had a body control module go a little crazy, but resolved very quickly at the dealers. A car is a sophisticated piece of equipment, they all go wild, if you haven't had any issues consider yourself to be lucky, you are the exception, not the rule. A friend of mine took A risk and purchased a Lexus that needed work.... Dealer told him he needed more than 10 computers/modules replaced.... It happens to all cars not just bimmers. Wouldn't give my m5 up for anything.
hopefully this was just a one time thing. I can definitely sympathize with you in situations like this.
Mark.