This image shows how the Stemfie3D car looks when 3D-printed at 200% scale.
If you make such parts, it is advisable to increase and adjust the XY horizontal expansion in your slicing software to achieve better tolerances. Larger scales tend to create bigger gaps which need to be adjusted accordingly.
Making such larger STEMFIE sets can make it easier for small children and people limited dexterity to play with this toy. Please supervise children while playing with STEMFIE to avoid a choking hazard.