Anchorage in winter:
They DO NOT use salt on the roads up there, just sand, so you don't have to worry so much about rust. Because of this, the roads can be slippery and everyone has two sets of tires and uses studded snow tires in the winter, which really eats up the roads. You will notice all the roads are rutted out because of the studded snow tires. I think your car will be fine for year round unless you live out in the boonies or way up on the hill.
You definitely want a block heater, even most gassers plug in at night up there in the coldest months. I don't know anything about fuel heaters. We lived up there from Feb to Jun this year (my Mercedes stayed in MN) and I think it was about 5 below every morning for 5 weeks straight in March.
In Anchorage, it really doesn't get colder than 20 below, so I guess that's a plus.
We absolutely loved it up there.