do they fit together? I tried a mustang 18" spare a few months ago and it fit the car, but I had to remove the a/m red caliper cover to do it. I am dropping of the car tomorrow to have the snow wheels installed, since the pirelli pzeros are done at 19k miles, and was hoping to tell the dealer tech to worry about them or not worry about them. I'd do it myself at home, but it's too cold and already dark by the time I get home.