CSR Elite isn't out yet and CSR is basically the same as GT2 which means it'll work perfectly with GT5.
There are no reasons to believe that those wheels won't work with GT5, they have always worked (Fanatec wheels) and they always will work with GT5, nothing will change.
Apparently the porsche wheel is a little heavier than the new CSR rim as well as some (updated electronics). No clue whats implied by that but thats what was on the site.