Had mine out flying today. Very impressive. Very little vibration. The only thing I have is some missing in midrange but that might be because my needles are still a little too rich. Also could be that I need to plumb my carb vent to the fuse or somewhere less gusty than the cowling. This thing has a TON of power on the stock exhaust. Pull out of a hover is very impressive on a 17#, 4.5 ounce PAU Edge. Starting is effortless and needs choke if it cools off to the outside temperature completely.

IMO low needle should be set so that the engine bogs slightly while it's warming up. Then after it warms up it should snap right up. I have mine very rich for break in. I only have a half gallon of Pennzoil 32:1 through it. The transition is instant. I had a DA 50 that would dead stick while inverted at idle every single time. I tested this in a few waterfalls and inverted elevators and it didn't miss a beat. It's unreal that I spent $300 LESS on this engine to fix that problem.