Had our first considerable snow fall last night and first thing this morning after dropping my daughter at school, took the wife's Q50 out in the snow before the plows came through and shot a little video.
This is an AWD with Tech model and stock all season run-flats. I tried to do donuts in an empty parking lot with snow, accelerated and braked as a hard as possible to see the reaction of the Q50. My objective was simple to do things beyond what a normal person would do in snowy conditions. I did all this in Sport Mode. I was deciding if I should get separate set of wheels+snow tires.
The absolute first interesting thing I immediately noticed was that when the ABS kicked in, if the car was sliding upon hard braking, the seats belts pre- tightened quickly considerable (with the Tech Package). They wouldn't let loose for a few seconds afterwards. Definitely keeps you in snug. Hence my groaning in the video below.
Also you will hear a faint "bird chirping" noise (turn up the volume all the way) when I was doing donuts, that is the VDC/TCS systems going crazy.
Overall, I am rather impressed with the tires for hat they are. I already know how well the ATTESA AWD system works with my history of Nissan and Infiniti cars, but the tires I was afraid of and I would conclude that they are better than "all-season grand touring" tires like Michelin Energy-X and slightly worse than "dedicated snow" tires like Blizzaks.
Here is a video. Sorry for the groaning, the seat belts got tight quickly and the ventilation system noise at the end of the video.