I think these are awesome, but I don't know what they are! I see similar wheels, but I can't seem to find these specific ones. Does anyone know?
63.3mm is our bore size (roughly 2.5") So one that is smaller would need to be machined wider, that isn't always the easiest or possible to do; depends on the wheel and the person doing it. Now going from a large bore, like 73mm or something is easier. You can find a hub centric ring to fill the difference or just mount lug centric.What I can't remember offhand is the hub bore you need. The 5x100's (18x8) in your link showed 56mm & I think that's on the small side for Focus.
I'd suggest something other than an 18" wheel for our gen Focus, they just look too big imo. If you were able to get hubs/rotors drilled, the wheels you linked would cost you $3200. I havent found any of them used but i have found LM's for less in a 17x8 and a doable offset. No idea if its an offset you can get hubs/rotors drilled for though