We had the opportunity to see the 3 GT in a private room in Brussels, without any disguises. It's quite similar to the sedan, at least the front, and similar but not so ugly and high as the 5 GT at the back. The headlights seemed to be those of the sedan.
Dashboard is also quite similar to standard 3 with a bigger (?) navscreen.
The big difference comes from some higher roof and the huge leg space in the back seats. It feels like there's 10cm more than my F11.
The room was not big enough and to cloudy to get a good general view of the car.
No pics: we had to put our cellphones in special bags before entering the room.