We have a BMW 3-Series auto which came with standard Continental tyres (not run-flats) and all I hear is that this combination is probably not going to be too clever when the snow comes (we live Scotland). No-one local (including BMW) is prepared to store wheels for us. So, is our only option to fit winter tyres on the current alloys and switch them back in the spring and so on? Is this a sensible route to take or would the alloys suffer with changing the tyres twice a year?