Cold temperatures are absolutely related to shortened battery life. It's basic chemistry. Especially if it's -60 below zero. I could be wrong, but if it's -60 that must include the wind chill. At -60 you'll have problems with gas freezing and oil viscosity issues. Just because I had to the record low in your city was -40 in 1951. Since 2000 the lowest temperature was -26 in 2009.
It sounds like the Impala in this case has something that's causing the battery to drain that the BRP. BRP typically only handles things like dome lights and the light in the glove compartment. Assuming you have nothing plugged into the power outlet which I assume you checked, I know in some cars the BCM is a likely culprit. They manufactured a bazillion impalas so there must be some information out there about the issue.
I'm not sure where the logic is that a all batteries, tires, and oils are the same. From a philosophical point of view, yes. In a practical sense, no. You're telling me there is no difference between a $35 tire vs a $250 snow tire? Yes, they'll get you from point A to B. But the handling and longevity will most definitely be different...
Daewoo are part of GM which means they share parts. Doesn't necessarily matter where they're made. They keep their costs down by recycling the same parts throughout all their cars whenever possible.
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I don't think the differentiation was clear, especially with so many conversations going on at once.
