Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3099588.

Bigger air pipes than the original, because there the balloon attachment was much too small and the car rolled really slow because of the tiny exhaust holes. As my son managed to break the printed axles, I switched to DIN 912 M4 screws with a non-threaded part below the head and created new wheels that run smoothly on them.