Maybe that photo could hint at some customization features?
Completely new front bumpers rather than just the addition of a front-splitter as seen in GT5? Additional air-vents on the hood and side of the car? Side exit exhausts? Branded tires?
It looks like it could be an upgraded SLS rather than a GT3 variant as the doors still look like gullwings judging by the doors lines on the roof, rather than regular opening doors which are likely to be found on a race car version due to safety if the car rolls on it's roof.
However, by looking at the image below, it's much more likely that its just a plain version of this.