[Magesmiley]

A usability question now... for all of the various tokens that you seem to be stacking on the bases (and which I would presume have a tendency to fall off when you move the vehicle), have you considered something other than cardboard counters? Maybe plastic clings (ala Colorforms) or some sort of holes in the base for pegs?

And... that's the first time that I think I've seen the base with the gap underneath.

Other questions:

1. What is being done in the picture with the car with the blue stand base? Is that a maneuver, skid, or something else?
2. How big is the mat you're playing on?

One last observation...
The raised bases with room to slide a stick underneath got me thinking a bit. If you made the raised portion of the back narrow (just in the very middle, so there'd be a fat raised area in the front and a narrow area on the back) and used something narrow and rigid, such as a thin piece of strong plastic (or maybe a coated piece of steel wire like what Steel Sqwire used for their spell templates) to measure movement, you could mark the angles on the base for the different turns, and all you'd need for maneuvering was the stick for measuring how far. Essentially you'd just slide the stick under the base, align the start of the move on the stick to the corner you want to turn on, adjust the stick to the angle you want, and look at where the stick is poking out on the far side to see how difficult the maneuver is (based on the markings on the base).

That might add too much to the cost though. But, the tradeoff would be being able to do bends with just the a simple, straight, movement stick, possibly saving elsewhere on components. I can elaborate further on this if what I'm describing is not clear.