If the SD is designed to fit in the eight vehicles it will fit in the hyper 7 but will need shims to take up the slack as the losi diff is shorter overall. If it fits the std spurs for the losi those have the same bolt pattern as the ofna/kyosho.
I would like to try one of these in my Muggy... Wonder if it will handle the 1521 on 6s.
Since you don't race, would it make a noticeable difference?
I would like to see how it does as a center diff. Fully locked (or whatever it can do) on power would limit the front wheels blowing up, and it would still turn well off power.