Guys - it's not just the box that changes. Your dish has a little doohicky sitting in front of it - the part that sits facing the dish on an arm, and the wiring comes from this. This unit is your LNB. This is what decides what codes are needed to go through the cable to your box. Standard Sky LNBs have one output, but Sky + has two, and two cables from it. Note that you can get 4 outputs cheaply enough too, in case you ever want to put in another box.
SO: The box changes, but so does the physical dish configuration.