How else to winterize your car.

Keep your heat selector in the full hot position. These cars don't have a coolant flow control valve, you can't stop the coolant from circulating though the heater core. Instead it just meters airflow into the cabin between heater core output and cold air. Point is if you leave it on cold waiting for the engine to warm up you are probably just wasting heat.

Put a block heater on, it needs to be plugged in one to two hours depending how cold it is. It will not get the coolant temp hot enough to register on the gauge but it will considerably warm it up and make heat come on after only a couple minutes of driving and reduce engine wear.

I have rubber wrapped winter wiper blades which will not ice up. You can buy a washer reservoir heater which will help alot in melting ice off the windshield (I don't have one yet). PEAK washer fluid says it is good to minus 35 degrees, I call BS, washer fluid WILL freeze upon contact with the windshield at around 20 below.

Also the little mudflaps to keep trash off the sides of the car and dramatically reduce the chances of rust. You MUST take your car through a carwash (including underbody wash) every other week as well.

Look for cabin drafts that let heat out faster than you can warm it; the doors and their seals cause the greatest leakage if not in proper condition. Check that hinge bushings do not allow sagging, the door vapor barrier is fully airtight, and the rubber seals are good.

As long as we're on the subject of the doors, you can coat the seals with silicone so they will not freeze the door shut, and if you can get the latch mechanisms out it would be a great thing to pack them full of moly grease so they don't seize after freezing rain.

3M makes some kind of 1" foam I think, if you want to go the extra mile and get it inside your doors and under the headliner.