Are you talking about 5th gen or 6th?
I wouldn't minda 6.2 di, but would rather have a 7.0di.
I'm not too interested in a 5.3 in a car.
But in a 6th, with the new cafe standards, I can see them using a smaller displacement gen 5 v8 with either turbos or sc. In a 3500lb ats based camaro, it would be awesome.