Polishing the intake ports will actually reduce the power. The roughness creates turbulence in the charge which helps keep the fuel in suspension.
Polishing them allows the fuel to drop out before it gets to the combustion chamber resulting in a lean mixture, high combustion temps, reduced engine live and loss of power.
If he, really wants to polish something, polishing the exhaust port is worthwhile, it improves flow and reduces carbon buildup.
Or you can just let him detune his engine to make roosting him even easier.
--Ron.