I was getting some tips from the Heli mechanic from my LHS about engines, this guy is like laboratory tech when it comes to them....he showed me his "log" of how his V-spec responded to different fuels....one had 25% and the other had 30%....from his lap times and mileage I could see NO difference in the performance from one to the other....but the 25% mill had 13gallons before it popped and the 30% had 9.5.......HMMMMMMM I think my next mill I'll be running 25% from the Get go......