It's plenty of power. I have one now with a .90ST. It's my second one. If you want to hover a lot put a 4-C in it. Other than that it's perfect. With a little modification you can even use the stock muffler. It makes more power than a pitts style. I have flown mine with a MA 14x6 and a APC 13x8. The 14x6 is better all around. The 13x8 is faster. These things will haul a** for a bipe. I need to try a 15x4W to see if it will hover better. Later David