First, there is nothing wrong with the car itself (however, you may need tires). How much experience do you have driving a rwd car in the snow? I have only owned rwd cars, so based on my experience, including in the gs, my best advice is to turn off the VSC (you could turn it back on once moving), turn on SNOW button, and last but most important, add some weight over in the trunk (i.e. rear wheels). I use a 50 lbs bag of dog food (or two) and it makes a huge difference.
FWIW, I think the GS does good in the snow for a rwd car. I only have 30% tread left on my Pilots too, and it does fine.