I agree. Even my 18" Bridgestone Duelers are not great in snow compared to a dedicated winter tire. Our little Accord has them and runs circles in the snow and ice. For that reason I am getting a 20" wheels and tire set up and use the 18" for winter tires on the X5.

If you go none run flat and non EOM you can get away paying less. It is up to you. You also may find some used 18" around. Good dedicated winter tires are good insurance as you do have some hills and bridges there.