^^^That's great, but (and I'm almost positive that BRGT350, and others who are versed on the topic, will agree with this), you
WANT that side wall flex/'squishiness' in a winter wheel/tire setup which is going to be used in actual snow conditions, as it helps promote tread void emptying of slush and snow as the tire moves along the covered surface.
Stiffening up the side wall with a stretched tire, on an 8" wide wheel, helps to NEGATE this process, and helps to defeat the very purpose of a winter setup for all but just cold/
DRY conditions.
I had 225/55-16 winter tires on my 16x8 factory wheels on my Z28, and I thought THAT was making the side walls WAY TOO rigid for effective winter SNOW use!