captinjohn:
Diabo has a very good point though. You are all talking about modifications that makes the engine make more torque and/or power around idle and right off idle, WHY? Except for taxying or that 30 lbs plane with a 200cc gas engine hovering, you never have the engine in that band and needing to make power. There is almost no load on the engine at idle and low rpm when turning a prop. If your engine doesn't idle low enough, or responds well right off idle, it is probably a tuning questions and fixable.
DKjens