Good question... my old ET5 was darned good and definitely within the ball-park of the original GAT. I presume with the GAT2 improvement the ET7 would maintain the relative relationship. If someone could compare the ET7 to the original GAT, that would be very interesting.
The ET-5 and the ET-7 are very similar in dimensions, but the ET-7 weighs 9 lbs less than the ET-5.......19 lbs vs 28 lbs. That makes me wonder what was eliminated that resulted in a 32% reduction in weight for the ET-7?