Thanks for your advice.
But here (in Brussels) snow and ice on the road are also very temporary situations. I suppose (my IS250 will only be delivered next week ) it is just for those gentle and not so gentle slopes that I would really need them. On the flat snowy stretches in between I figure they would just come in handy.
Also, if you believe the publicity, they are very easy to put on/off. So you could use them only on snow/ice and take them off once you have the chance to find yourself on a cleared road.
Any idea how long these socks would do their job on really snowy/icy roads?