May I offer a suggestion not only to Bert but to anyone thinking they need the latest and greatest motor.
Work on your bloody driving
When you can run each and every race and get at LEAST 95% consistency, then perhaps look at motors / lightened pinions and whatever to get that last tenth. Until then YOU are your own biggest obstacle, if you spent half the time practicing as you did flooding internet forums with half baked theories you'd be a world champ in no time!
I've started my son with a fixed timing Justock 21.5 motor and he's not getting anything faster until he gets the consistency down.