The "magic" is a modification in the crank and case designs, the addition of a third bearing, a Mahle cylinder, and effective porting. They are high in price, about equal to a DA though, so you won't be getting one on the cheap.

About the only thing that can effect the performance of a new one would be either a bad carb or incorrectly set timing and the condition described in 3DDino's post fits timing to a "T". Low rpm with a crappy prop and even lower rpm with a good prop. The timing is probably currently set at zero/TDC and simply correcting that will bring the rpm up a thousand or more. What's great is that you don't have to buy anything or remove the engine for shipping to perform the fix.