THIS FINAL collaboration between Mercedes-Benz and McLaren is, like the Coupe and 722 Edition that preceded it, a technological wonder. It shares the same carbon-fiber-reinforced-plastic bones and 617-horsepower, 5.5-liter supercharged V-8, but the Roadster’s semi-automatic cloth top opens up an entirely new, more pleasurable dimension to the thrill of driving the wickedly fast two-seater.
Because the SLR tub is so stiff, no structures were added to match the Coupe’s torsional rigidity and, except for a new, stronger tri-axial CFRP weave in several components, most revisions are above the beltline: new windshield frame, rear fenders, trunklid, doors, and A-pillars integrating steel tubes as part of a safety system including two non-retractable hoops, six airbags, and sophisticated traction control.
The chart says 0-to-60 mph in 3.8 seconds (and we saw 0-to-124 mph…