Mercedes-Benz knows its high-performance vehicles, and at the pinnacle stand two model lines: the SLS AMG and the AMG Black Series. Now the two are set to combine for what promises to be the most devastating performance vehicle ever to wear the Silver Star. Following earlier test mules spied last year, this latest batch shows a white prototype gearing up for its market introduction. A more aggressive body kit is apparent, but the best parts lie underneath the skin.