How much weight should I put in my trunk for winter driving in Colorado?
Other than the fact this is a terrible vehicle for snow just call the service department at your dealer . Surely someone there has experience with this problem.
If you do add weight it needs to be above or slightly in front of the rear wheels.
If you are in Colorado, and drive a Miata, I’d suggest buying 4 winter tires on steel wheels and installing them for the entire winter. Put the nice alloy wheels and tire back on i the spring. The car will perform WAY better than just tossing some weight in the trunk. In fact, they will transform a scary winter car into a secure one.
Check tirerack.com for wheel-and-tire packages. Be sure and search for “winter” tires, they are specifically made for ice and snow.