I plan to buy a second set of wheels for snow tires and do the change myself.
I also wonder about their formula for flat tires, one every 100,000km. Here, in the Northeast, where the severe winters generate a need for an occasional new roof, roofing nails are everywhere, especially after it rains. (Roofers drop them by the hundreds on the job; they fall to the ground and eventually wash out into the driveway and street). I am still planning to get a miniature spare tire or two (one for the different size snow tire wheels), and throw them in the back seat like the German test drivers :), or the trunk.