3D Printed wind up car

This working prototype is the result of lots of hard work, a few print iterations, a TON of design iterations and a bit of dumb luck (in the form of a few lucky guesses) 
Link to Car
I was very excited pulling this little toy car out of the box when it finally arrived and have been quite surprised by its performance after only a few actual prints of the whole wind-up gear box system! (I was surprised it moved at all)

At this point in time the car only moves about 50cm once fully wound up but i hope to increase this distance in the future!

This Wind-up toy car is printed in one piece by using Shapeways SLS nylon printer and comes with it's own key.
It can be wound up with the key, or by simply pulling the car back.

The wind up car at the moment is available in Beta as i'm trying to work out a few kinks
(the main one being the fact that the car required quite a bit of manual cleaning to get the parts moving)

Through the Beta processes i'm looking for any suggestions to improve this design! 
(I have already uploaded an update that improves some aspects)