I'm given some encouragement by the fact that there are clearly 2 styles of test cars running around, differentiated by their different roof seams, and buttress shapes. If I'm correct then I'm expecting a Ferrari or McLaren style folding hardtop.
The "convertible" has a roof seam about 6" in front of the rear of the door, if my interpretation is correct. Other test cars have the seam almost lining up with the rear of the door. Interestingly, the car covers are also different on the 2 styles, with the "convertible" cover coming further forward and covering more of the B pillar. Consistent with the Ferrari style solution are fat buttresses on the "convertible" cars.
Additionally the convertibles have the exposed rearview camera nub whereas the coupes place the camera in the car behind the rear window. Presumably the camera will fold away and the mirror will revert to being conventional when the top is down.
Comment