One piece? Two pieces? or three pieces? Hmm.... Stop guessing and just take the head apart and look inside. From my understanding, there are three pieces inside the cowl(not including the cowl itself) it'll require to loosen up the cowl and the head adaptor inside before doing this mod. It'll take some time and study before exaction as always. Not going to explain much as English isn't my first language. Get a Facebook, I'll walk you through the tutorial by pictures when I get the chance.
Is it with doing it? Only if you end up loving the figure as I do. Straight out of the box, it looks like a stranger to me tbh. Everyone who saw this figure in hand shake their head sideways......
It will require lots of time to get the figure to look like my or better, but for $100, why not have some fun : )