From a practical perspective, it seems that drag reduction and prop selection are about the most critical variables in the search for maximum speed, right up there with engine selection. The speed fans here do seem to have given up on drag reduction, in a sense, since they are flying 'stock' Whiplashes, Diamond Dusts, etc., and choosing engine/prop combinations to maximize thrust. I would say there is quite a bit of room for drag reduction, if you're willing to spend some time fairing the engine and burying the servos.

banktoturn