Phone [Q] what version do i get

I currently own a kitkat and want a loki compatable s4 but what one do i need i saw a MF3 but guess thats the version after the patch. So what should i get. Basicly what do i need to look for so i know i can install cwm? Im thinking i should bite the bullet and get a gt i9505 but then i dont know if i have to watch out for not getting a updated one or does it matter??