I just picked up my second X5, a 2007 X5 Sport with 20" wheels. It needs new tires and I think I'm going with the Continental DWS's.

My question is; in addition to the new tires, I would like to buy an additional set of winter wheels and tires as I live in Buffalo, NY (plenty of snow and ice). But I want the OEM look as I have the 20" Y spoke now.

So should I go with a 19" setup since the 20" setup doesn't seem to be winter friendly? And if so where should I buy them from at a decent price? Ebay?
Should I look for a package setup or buy the wheels and tires separately? Remember, I DO NOT want aftermarket wheels.

Thanks for any insight or advice.