Anyone running a block heater? 0249953 Experiences? Any idea on turn-off temperature (if at all)? I see that they're 400W but can't find much otherwise. http://www.thesaabsite.com/shop/search.php?search=block+heater&m=6#linkbar Part number looks to be the same for the 9-3 and 9-5 4-cyls...