So I don't have a Q50 or even an AWD car right now (I have a 2012 G37S Sedan). However, I did own an 09 G37xS. To me the AWD was kind of meh.
Its a RWD unless it slips. Then sends power up front. It was always contested on the G Boards about the Snow button or now in the Q50's case, the snow drive mode selector. Yes snow mode deaden's the power. However, nobody can ever really provide documentation that the car ALSO starts in 50/50 torque split.
Cars like Audi and Subaru have a constant torque split in their AWD systems. The G/Q does not. Those cars seem to inspire better snow driving.
I played with my G a ton in the snow (I live in Buffalo). In snow mode with heavy throttle the back end kicked out until it realized the slip and then sent more power up front. Had it started in 50/50 I would be able to pull away with MUCH less slip.