I'm getting an X5 35d with sport package and its 19" wheels. I plan on putting on 20" 214's for most driving in southern CA. When driving to the mountains in winter, I figured I'd put on the 19's.

I'm new to the idea of driving an SUV in snow.

Questions:

Should I get snow tires?

Will I likely need chains even w/ snow tires?

If chains are required w/ snow tires, should I not even bother with changing the tires at all and use what came on the car w/ snow tires?