My information is that the 2016 and up have additional clutch packs in the transmission.
My tune with a heat exchanger makes 511 wtorque...I'm not sure I trust that, but everyone tells me they have no problem and some of those guys have been beating the bejeezus out of their cars for upwards of 15k miles in some cases. I'm talking drag strip racing every weekend.
So far, I have not heard of anyone breaking the transmission, and only one guy who broke a half shaft.
My problem Is I come from a 4th gen Fbody crowd. Our rear ends and transmissions shattered if you looked at them hard. But I am becoming more comfortable with the powerlevel on this car and I am not seeing any issues. Knock on wood...