That looks like fun! :) Nice catch. One minor nit...I keep getting drawn to the top left corner. I know it would screw up the aspect ratio to crop down from the top some. Hmmm. Worth considering I guess. Good luck in the challenge.
Always a good place for speed and a splash of colour. I think to lift this points wise it would have been good if you could have captured the kart coming out of a corner, or even approaching you, rather than just having passed. That way you get a little more dynamic tension and involve the viewer more. Good crisp shot though.