What if anything would change if an F23 were bored over from 86mm to fit in 86.5mm pistons? Displacent? Compression? Any benefits or gains from this?

 

you will gain a tiny tiny bit of displacement. that is all. nothing really measurable.

overboring and then honing the cylinders before building the motor is a good idea just to get new, completely round cylinder walls to work with.

 

Ah, so it's just a good thing to go along with the motor build huh? Will this weaken the cylinder walls enough to be concerned about boost levels?

 

nope won't weaken them enough to worry about. 0.5 mm is damned small. I wouldn't be worried about it unless going for 450+ HP levels, then I'd be worried about stock sleeves in general.

 

So would it be beneficial to bore any larger and use some say, 87mm pistons?

 

I would go with stock bore for some insurance. If you scratch a wall or slightly melt a piston you can still bore out and go to the next size up.