I think you'll be pleasantly surprised. I think the X3 is at the top of the pack when it comes to SUV handling, and, although I haven't raced ours, I've made some moves that would have made my hair stand on end in just about any other vehicle but which the X3 handled with aplomb. The only thing it lacks is the straight line power, but fortunately that aspect is balanced out to a large extent in an autocross by the handling.

Good luck with it, and keep us posted on your experiences.