Built as a study in styling, the Opel Coupé Diplomat saw new design director George Gallion feature a one-panel windscreen and door-integrated side windows – pivoting forward to access the cabin. Aerodynamics heavily informed the front-end and overall chassis form after rigorous wind tunnel testing – uncommon for a vehicle of its time. Ergonomics, too, were considered throughout which extended to the interior that exhibited a sleek, integrated telephone unit to the centre console.