Hey there ripper, I am a complete newbie and my son and I started riding back in April of this year. Being 46 years old, I have been a little slow to develop the skills and balance to ride a standup. I also ride a 750sxi (skat trak impeller is only mod), and my son's ski is a totally stock 550sx. I have always found the 550 hull to be much more forgiving in the turns, and seems to be less "tippy" when on a plane compared to the 750 hull. I have been able to advance a bit since April and am finally starting to carve the turns a little tighter, and am jumping wakes, etc. I recently installed the Blowsion destroyers on the 750 in an attempt to tame down some of the tippyness and sketchy balance in the turns (as I have read many others comment about).
I have had the sponsons on now for the last 4-5 trips out, and I have to say that I am finally starting to notice some major differences in how the hull behaves. In the beginning, I was a bit disappointed that I was unable to really notice a major difference, -well, that was because I wasn't really "pushing" the ski, or my abilities at first. I have since built up some confidence in both the ski, and my abilities. The sponsons seem to have tamed-down some of the high speed wobble (that some guys call chine-walk), before, at times the 750 would decide to wobble back and forth at a certain speed and just put you in the drink at 40mph, -it seems much more tame now. I have also noticed how much better it handles in rough water, -before it would really "hunt" in large waves, and the hull would constantly be leaning right and left, -now it just seems to skip evenly with minimal tipping when in rough chop. Before the sponsons, turns always seemed iffy, -and occasionally the hull would either come unhooked, -or the thing would roll way too much to the inside, -even with max power on the pump. Now with the sponsons, I can really lean into the turns and apply as much power as needed to carve the turn. In a squat stance, I can literally lean in, crank the bars and go wide open throttle, and it will not come unhooked, it carves well beyond my abilities as a rider right now, my plan is to burn fuel and get as much tray time as possible on this thing to be able to take full advantage of the skis potential.
Occasionally my son and I swap skis just for kicks, -and even he noticed an improvement in stability, -before the sponsons he hated it because (in his own words) was way tippy compared to the 550, -and how right he is! I think the sponsons were money well spent, if for no other reason than they seem to have made the ski easier to ride, -and it handles better also.