Thanks, Max. I see the iSpeed at 163 has a 68 waist, while the Super Joy is 75.
The TR is about the same for the two skis at 163 -- 12.7 for iSpeed and 12.5 for the Super Joy.
So the iSpeed is faster onto edge, which I'll feel on hard snow.
I'll pay attention to that.
Dunno how the stiffness compares.