Yes, checked that out too. But discount tire has less RIM to choose from. And the base price is a lot more expensive (maybe 30-40% more) to begin with. So it ends up around the same.
To my limited knowledge...4 wheel drive makes you easier to start the car from snow...but snow tires have better friction on snow so you will be easier to "stop" the car ....有錯請指教。。。