The B4 is an excellent choice. Brushless is allowed in every class. As for motors you can run whatever you'd like in Mod 2wd buggy, stock I think the limit is 17.5. It may be 13.5. You could give Steve Hale a call at 816-540-5584. He owns the track and he can answer every question you could ask. As for tires Suburbs are what work, or atleast that tread type. Each brand has their own version.