This was designed to be printed in standard orientation at .2mm layer height, with a pause to insert magnets. Included is a file to test the fit of your magnets. The current design expects you to glue it to your car, this works for mine because I had an unused panel.

I used 15x6x2mm Magnets 

Mine has extra magnets, because my printer can't used the pause command, so the gap was larger than the magnets could pull. I tested if it printed properly, and it should work