Why is this a big deal? Because it means a tuner finally has access to the ECU. This means more parameters can be modified but it also likely means that the dealer will know the car was tuned. GAD Motors is showing some strong numbers as the dynograph below indicates 427 horsepower at the crank which is inline with the other Stage I piggyback tunes on the market. They do not provide a baseline however so it is difficult to gauge the before and after numbers.
This is a major step forward for the platform if accurate and we would like to see more details from GAD Motors on this development. It will also be interesting to see if this 'crack' trickles out to the rest of the AMG tuning community.