I know this topic has been discussed, I've read the previous threads on them but I wish to talk about it again. My question is, are there any true gains/documented gains with porting or even polishing the exhaust port? I know slightly cleaning up the trailing edge of the port will help with the carbon that usually builds up there, but I'm talking about actual gains and not just some reliability improvement. I'm aware that a water jacket runs really close to the port, but how close? Is it possible to port the roof of the port very slightly to lessen the bend coming out the engine? If that's not possible, slight cleanup and porting to a mirror finish to help air escape should net a couple hp at the very least right?