Good question. Besides the obvious change in the empennage…..the SuperMax supports a 76 hp VW vs 50 hp VW for the V-Max. The empty & gross weight also is 100 pounds plus heavier than the V-max too. I believe the SuperMax includes a welded gear assembly vs the built-up gear. Haven’t seen any published performance numbers for comparison. Given that both models are nearly identical I would bet that cruise speeds are fairly close but the SuperMax should have a better climb. But you’re right, just not a lot of info out there.