I concur on the fuel! Here in so cal we have Performance Plus. I prefer it's YS 20/20 blend over the Powermaster blend. But you must consider the #2 rule in RC which is:
Always use the same fuel! The motor will get used to the mixture once you have it dialed in. Fortunately you will find the YS needs less tweeking if you change fuel. Unfortunately you will find that the YS loves a higher nitro content! They love 30% heli blend but your pocketbook wont....