Up until this point I have not radically changed the timing of an engine. I mostly flow the sleeve and wont change the timing profile as that is the characteristics of the engine. I do not want to change that. By lifting the exhaust port I am only moving the power band ex let say the power band was 7000rpm to 34000rpm, it will be 9000rpm to 36000 rpm.
I recently changed the this on my P5X.
The engine had just rediculopusly too much bottom end. Now I find good bottom with a phenomenal midrange and very good top end.

Everyone modifies in their own way. I only mod for more overall power and economy, maybe if it needs better top end.