I find my 17.5 Ultra premium to have great power. On Fred tech with my 417v5 I was able to keep up with Rod which I've never done before and took the fastest single lap of the day and the win. For TCS regional I was able acheive fastest single lap every run as well even though the car is grossly over weight at around 1530g.(i'll work on that... to much useless aluminums) Only wish I could have drove better. So far very pleased with this motor and I'll try it with my 1500+ rotor next time to see if it will perform better. I got a example where the rotor is fairly strong but not the strongest I've seen with R1