More like this?
It depends on the light and the difference between the two cars is more obvious in overcast light, whereas in bright sunshine they look quite similar and the MG6 looks much brighter. As far as I know they haven't changed the colour options at all, and the GT is available in silver, grey, orange and blue which are metallic and red, white and black which are solid colours.
Have fun finding all the toys and tricks on the car.