Yes, it's Summer basically. But I'd rather sort this out now while prices are a bit less...

My X5D has the 20" wheel option.

What is the best option for snows?
A. 20" Snow tires on my stock rims?
B. Second set of 19" (or 18"?) rims with snow tires?

OR since I live in CO should I just get all seasons?

All help is appreciated.

Thanks,