From there supported memory list(PDF file on the site) it says you can use 2 x 4 gig stick from Kingston. I have seen Elpida memory sold under there own name as well. There is another set listed there as well.
8gb was just a wondering
i think i'll get 4 gb and that's fine
the problem is i live in brasil and i'm going to us in december and i was planing shopping because in my fuckin country we pay double you pay there
eg. an 360 arcade at release date costed here 1800 reais which means U$$900,00