The apple website shows its got a removeable bottom panel. I looking at the cheapest mac mini, as it all seems fine for what's need it for but I'd like 4gb memory. I see in the configuration it's either 2x1gb or for £75 extra 2x2gb Can I upgrade to 4gb for less than £75 that apple charge in config? Can I stick a 2gb alongside the 2 1gb cards or would I have to remove the 2 1's and put 2 2's in? And, is it a simple case of unscrewing the bottom and slotting it in?