No clue, about fps, but the 4k textures are only shadowmaps, not the actual textures so it's, in my opinion, useless.
I uploaded them just because i rendered them on that size and i know there's some maniac out there that loves useless things that make their pcs slower... xD
Anyway you can edit any of my mods as you wish, the only thing i pretend is that everything based off my mods must be released for everyone.
Harrison15 about PXRZ: he turns everything into a pretzel in his head