I think it's the "Emperor's New Clothes" feature (ENC in BMW acronym-speak) - there really haven't been any different M5's since the E39, but, once switched on, it makes the E39 M5 look, feel, and sound like whichever later M5 is selected - I'm guessing some intrepid journalist deciphered the arcane sequence to turn off the feature before the picture was taken.
