Looks like somebody's been stalking Q
From what I understand, and that is not a lot, there are a couple advantages to doing the window but from what I think I remember there was no real HP gain or reliability improvements. (supposedly helps with cooling or something?)
On the skirt cuts front/rear skirt cuts this can affect timing/power curve but you need to watch for skirt cracking & flexing which will reduce the number of hours the piston can run reliably.
The other thing is how is your porting set up and what pipe are you running will have effect if these mods will be beneficial or they're magic fairy dust.
Motor Geek would be the man to talk more about the real scientific pro &/or cons of doing these mods.