FWIW I determined that the Shorai was nothing but an overpriced Paperweight. That's said, given how light it is, it's not even a very good paperweight. My bike is proof positive that it is not required. You can buy several of the more powerful starter motors for the price of one of those batteries, and to be honest, it doesn't take much longer to swap the motor than it does to swap out the battery. I know what it's like to be stuck with a bike that won't start and I also know how it feels once the problem is solved. Not that I would ever ride in temperatures such as this but my bike will now start at -10°C or less with no issues.
I know some don't like the link at the beginning because it takes you to some foreign land but, in fairness, some of the links there bring you right back here