What is the advantage of having oversize valves? how much difference will it make between stock, .5 and 1mm oversize? If I get oversize valves, what needs to be done on the head other then port and polish?

I'm a newb...so dont' hate me for asking stupid questions...

 

turbo or n/a application?

 

Will go to turbo later on....but stock for few months...

 

Here is a thread discussed earlier that explains alot about oversized valves and bore size. Lots of info here https://honda-tech.com/zerothread?id=156070