actually bmw04series, DSC is on by defaut. you have to press the btn to turn it off. (
if you have the solid orange DSC light on, that means it's off.
if it blinks during operation, it means it detected a slip and is working.
tires are probably the bigger issue. not all a/s tires are good in the snow. (well even in my snows yesterday, i was detecting slip, but snow is slippery, and i know i'm way better off now than i would be w/ other tire setup.) goto tirerack.com and check out the in snow performance rating on your particular factory A/S tires.