Th unveiling of the Mercedes-Benz SLS AMG Black Series isn't that far off. Prototypes have been popping up in spy photographers' image banks for a while, now we have some video of the hardest SLS AMG the street-legal world will ever know.The specification remains a mystery, though, even down to what engine will find its way tucked well back under that long hood. The money seems to be on a last hurrah for the 6.2-liter V8, uprated to something beyond 600 horsepower from its current 563 through engineering and not forced induction. A report in Car and Driver predicts the Black Series will lose 100 or so pounds and get strengthened running gear to cope, along with the usual fare that makes every Black Series a volcanically hard performance tool. Scroll down for a look at the videos and to hear the sound through its quad pipes.