Sometimes on extremely refined race motors, polishing isnt best. Within intake systems, the surface is usually deliberately textured to a degree of uniform roughness to encourage fuel deposited on the port walls to evaporate quickly. A rough surface on selected areas of the port may also alter flow by energizing the boundary layer, which can alter the flow path noticeably, possibly increasing flow. This is similar to what the dimples on a golf ball do. Theres always the need ive noticed to refine and change performance in motors with humans. Its in our DNA, but in my opinion, if kawasaki's latest model H2 or H2R isnt polished after 90 trillion hours of testing, theres a reason. Just my opinion.