Ideal winter garage

Salt is a body killer! Previous (NB) models had a clear, somewhat sticky, plastic/ coating to protect the underside. I don't know if the NC has the same coating. In any case, regardless of what you do-- The garage will need to be insulated if you wish to keep things above freezing. Snow melt may evaporate , due to the normally low humidity in cold temperatures. A key to minimizing rust is to remove the salt residue from the car as soon as you can. A slightly acidic flush may help neutralize the salt. I grew up in the Midwest, and although we had lots of snow and ice in my hometown, the Chicago area put us to shame in terms of the amount of snow and the deep cold temperatures. I had a plastic door panel split, due to the very cold temperatures on a Buick that was just a few months old. And, this was in an unheated closed garage. My father in law's 70's GMC P/U had a body that turned to lace in less than five years due to the salt.

You beat me to it, Tim. Salt does no harm at subfreezing temperatures. But once the accumulated snow starts melting, it carries dissolved salt into every nook and cranny, and that's when the potential for rust begins. If you must drive the car on salted streets, best to leave it frozen, then wash the undercarriage when the weather warms.

Dunno about the NC, but older Miatas were not particularly prone to rust, as long as their body drains worked properly. It's good practice to flush the drains every time the car is washed, and unclog any that seem blocked.

When I lost my 1990, she had one tiny bit of rust in the right side rocker panel, about the size of a 50-cent piece - and that was after 12 years of her of sleeping outside in the winter here in Eastern PA. She spent her last 5 years in an unheated garage. Our area of PA relies heavily on rock salt and brine sprayed on the roads in the winter. I did not wash the undercarriage separately *ever*.

YMMV of course.

Iva & Vixen