I've got seven (7) of them and like them almost as much as my Aerotiger .36. I agree that the rear mounted needle valve is lousy...so are the venturis that come with them, basically just a straight through hole with a taper at each end. I make a delrin Venturi (.272") and drill the case for a through the Venturi n.v.a. The n.v.a.'s I use are either Super Tigre or the ones for the Evolution 60 NX. I also use the Thunderbolt R/C Long glow plug. These are the only modifications I make. The "secret" to getting great performance is using the right fuel. The manual is correct that Cool Power all synthetic oil is the fuel. It's only 17 or 18 % oil. These engines do not run well on 10/22. They don't run well on fuel with castor oil. I've got well over a hundred flights on mine and the cylinder still has a pinch at TDC. Favorite prop is an APC 11 1/2" x 4". Launch RPM is 10,000 to 10,200. I'm flying mine in a 50 oz. Caprice. Our field is almost 6,000 feet elevation. If you insist on running 10/22 you will have to add head shims to reduce the increase in compression which will result from the extra oil. When you do, it changes the run characteristics of the engine (makes it worse) and won't put out as much power. I don't understand the comment on the lousy fuel economy. Because of the reduced oil content in Cool Power, mine gets WAY better fuel economy then my Aerotiger, my Magnum .36's or my Thunder Tiger .36's.
One other thing, I've used Jim Lee's true Venturi conversion on one of mine. It works great...same performance as my venturis...and you don't have to drill a hole through the case.
Chris Brainard