I agree with T.O.M that these should not be needed on a properly cowled and baffled installation, I also agree with Truckracer that most of us are too lazy to install our engines properly so we go for the quick fix instead of realising the full potential of the engines

There is one very definite reason that I want one of these covers though
It is a piece of Bling that nobody else at my field has got yet - and that definitely makes it special