You should be fine with all-season tires.... Most people do fine with all-season tires, 2WD and 1500 pounds less. Also, most people have no clue that summer and winter tires exist.

I've always changed out summer and dedicated winter tires, but with the X5 I'm going with all-season tires year round in Chicago. However, there are no mountain passes for me to drive through, just the occasional deep snow on flat ground.

The Continental DWS has great reveiws, I was actually going to get them, but they have been backordered for a while. I went with the Yokohama Avid Envigor which also has great review and as a bonus are cheaper. I just got an email they shipped today.