Had a look at the prototype earlier , It is definitely a four door with conventional trunk. The upper part of the door line is camouflaged with the panel but also some rubber tubing which make it look like a door opening.
The hofmeister is sharp like the Coupe another clue is if you compare the interior shot of the pillar it does not match up with the exterior shot.
This is the more semi-commanding appearance of the 3er GT.
It fuses its appearance with more Coupe-hatch roof. Unlike this Gran Coupe which has some extra packaging tacked on to the rear and covered up to disguise some of the svelte lines.