Wait for the duel in the turn
Well you don't even have to wait for track vs. track comparisons. We know the M3 not only pulls more lateral g's, does the lane change and slaloms way faster but it will likely post better track times as well. Add DCT and the gap and effort to get it will significantly decline, strip and track.
This is classic AMG vs. M no surprises. AMG faster in a straight line, M3 on the track (again that has not been "proven" yet but I suspect that is the way the cards will fall. The two surprising role reversals this time are 1. The the AMG has good handling and steering as opposed to many complaints about the M3s steering and 2. The M3 is more comfortable. Odd.
Bottom line if all your need to feed your ego is the ability to best M3s at stop light or freeway races buy the AMG, simple!