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