Haile, if you want crazy unlimited sky tearing power, the OS 120AX is the way to go, use an APC 15x6 prop and mount the muffler in the pitts style and remove the internal baffle to have great roaring sound. All other engines are a compromise ! and I would definitely never buy a supertigre, it is cheap and you get what you pay for, after 3 or 4 gallons of fuel it will start loosing its punch very visibly, the needle will become hard to set and the engine will start dying in flight more and more frequently.