In my experienced years of engine building, all of the cylinder heads that i have ported and seen ported, the intake ports
were never polished ( mirror like ) Just the combustion chambers and the exhaust ports were mirror polished.
The original reason for mirror polishing was that the head was easier to clean during tear downs. Just like you see
in the picture of Mikes ported intake port, it's smooth but not mirror polished. Thats for better atomization of the fuel on
normally asperated engines. Porting and combustion design is very very important on normally asperated engines, not
as much so on turbocharged and supercharged engines because they force feed the engine with way more air and fuel.
A very easy way to gain horsepower is to use nitrous oxcide. With a small 50 HP setup it will work great on a stock
motorcycle, with better valve springs.