Coo, as far as performance goes on the Saito 100, its two years old. If something regresses over a two year period, it is hard to notice. I do remember being very happy with it in the beginning and over the two years of use it has been very reliable. That was on my 7 1/2 lb. UCD. My latest came out to 8+lbs. All I have to compare right now is the old Saito, swinging a 15" prop which needed 3/4 to full throttle to hang, with only the ability to fly out of a hover. The new YS swings a 16" prop and will hover at 1/4 throttle and climb to the clouds. This 8+lb. UCD is now an additional 6 oz. heavier with the YS. Weight, throttle settings and prop size is how I came up with an estimated 75% more power. Not a very technical aproach, I must admit, but seems realistic to me. BTW, the Saito was rebuilt twice, including bearings and cam gear and both times recieved approval from the techs, who had the green light to replace anything that was needed. As far as the YS 91 goes with 8% less power than the 110, I cannot verify that and it is the reason why I said 'do not quote me on that, I could be wrong'. Perhaps I was using the figures from the comparison of the Saito .72 to the .82 Thanks for pointing that out, so as no one else gets misled. Joe