For racing you'll have to choose between two wheels(MXB) or four(ATV). No need for a huge stable of cars for these tracks. Both vehicles have their pros and cons, but the four wheeled machine is a better starter model than the two. While the MXB is fast and nimble, it's also a little harder to control. The ATV is a little slower, but considerably easier to maneuver through the tracks. Once you are familiar with the tracks, you may want to switch over to the faster machine. There are some customizations for each ride, and they do make minor differences in handling, boost capacity, acceleration, and speed. The differences seem to be fairly minimal and have no bearing on the overall performance of each vehicle. http://naildbiter.com/d7jkI