Hey Connor,
Tall and skinny will give you your best performance in snow, so if you can find a good tread studable in the original size at a reasonable price, go for it. The 165/15 would have an 80 aspect ratio. I agree with you on studs. These fancy compound "ice" tires are great indeed...for the first 1/4 of their life. Not the best for serious snow stuff though.

But indeed, there ain't much out there for the stock skinny 15" rims.If you could find a 175/75, that would be great, but...good luck. Nobody makes a 185/70 anymore. Not at a reasonable price anyhow... and a 185/65 will be costing you in clearance. Anything wider than 185 is pushing it for the stock rims... ANd...depending on where you are, you also want to be sure you have enough clearance for chains.

I'm running stock 14" 240 wheels on my 164 with studded 185/75-14s all around. They work well, are about the right diameter, fit fine with chains, and there are about a zillion tire options in that size range.

What part of Colorado are you in anyhow?

-Matt
Fort Collins, CO