Matt, you are struggling with what every piped 2 stroke application struggles with. The change that occurs when the engine comes on and off the pipe. We sometimes have the mentalitiy that we need the maximum HP out of an engine, but what we really need is maximum throttleability (linear up and down). I"ve often thought the the thing to do is run a slightly bigger 2 stroke and put it on a muffler instead of a tuned pipe. I've run the OS1.40 on a muffler with very good results turning a 15.5 x12 4 blade prop.