i've had a few modded motors in my time and to be honest...a couple of them were worse off than stock...my best experience would be with Mark from Powerhouse Perfomance...he took the time to listen to what i wanted and then take that knowledge and turn out one hell of a modded motor (not just give you a package option)....i'm running a GRP non tuned .21 with his turbo mod and am getting almost 11 min of run time with an electric like powerband that just keeps going.....