Its interesting to note his story about dragging a Hayabusa. It appears that putting on a pipe would have a negligible effect for street riding. Lowering the chassis and working the clutch gives a huge improvement comparatively.
I've thought for a long time that these aftermarket pipes mostly give such a marginal improvement that the cost doesn't justify it unless you are racing professionally. Is 4 hp worth $700-$1000? I think not.
Most people put on a pipe first 'cause it looks or sounds cool. That money would be better off spent on suspension and other improvements.