I just got a Firepower 450 Sport from HeadsUp RC mounted which is a 220 watt size motor. I was unhappy with the flight times I was getting with a 10 size motor. I think this 450 size motor should have slightly more power than the original. If it would stop raining and blowing here I might get a chance to remaiden my version 3 Sensei.
Good luck to you guys going to the size 15 motor but I was not happy with getting just 5 minutes on a 2200 mah battery with my 10 size motor. I know I could have added more battery but I chose to go back to nearly stock power. It kind of fit my flying style anyway.
Glad to see the Sensei thread come back to life it was silent for awhile.