Georg Kacher - flat-out on Germany's Sachsenring race track in the
new Mercedes SLS AMG, chassis number 00045, a mildly camouflaged pre-production model. Ahead is an SL65 AMG Black Series--twin-turbo V-12, 670 hp, 738 lb-ft of torque--driven by Tobias Moers, head of AMG's r&d division, seasoned race instructor and today's pace-setter. Filling his mirrors, Georg Kacher's red gullwing keeps pushing harder and harder, even though its normally aspirated 6.2-liter V-8 is rated at a comparably modest 571 hp and 479 lb-ft. The Sachsenring has plenty of slow corners, lots of climbs and descents, two long straights and two very fast and very blind fourth-gear bends.

As Georg Kacher session progresses, this track is becoming a nightmare for the wide, fat SL, and dreamland for the light and nimble SLS. Despite the Black Series car's four more cylinders, 100 extra hp and 259 lb-ft of added torque, it's punished by its 551-lb weight penalty. The SLS not only uses a significantly lighter double-wishbone aluminium suspension, it also boasts a featherweight spaceframe body which tips the scales at a mere 531 lbs. Perhaps even more significant is the weight distribution. In contrast to the nose-heavy SL, the new gullwing places only 48 percent of its mass on the front axle and 52 percent on the driven wheels.

Read full Story