Thread is 10 years old. But in case somebody else wanted more info.
My Banshee is stock bore stock crank, T5 exhaust, shaved flywheel, 19cc coolhead domes. 93 octane.
Power band hits at 5500 and starts to drop off at 11,000 I can run 13,000 but you start to really notice the power loss.
Also! Once engine temps get over 150. You will notice decreased performance. And anything over 200 it's a real dog.