Mercedes-Benz doesn't have a rear-mid-engine supercar in its model lineup as Ferrari and Lamborghini and Porsche do, so it has chosen to create, with lots of technical help and finally assembly by McLaren, in England, a sort of long-nose, short-deck front-mid-engine supercar. The engines are built in Germany by Mercedes-Benz's in-house high-performance shop, AMG, and shipped to England for installation in these very special bodies.

The roadster bodies are completely new, not cut-down versions of the SLR coupe bodies. They are made entirely of three-layer carbon fiber at McLaren's race shop. Carbon-fiber reinforced plastic, or CFRP, is about five times stronger than steel in crush (or crash) situations, at about half the weight. (It's also a lot more expensive.) The one-piece body is then fitted with a huge V-shaped aluminum beam structure on each side that attaches to the front of the firewall to carry the engine, transmission, front suspension and steering. The carbon fiber fenders and hood complete the body.

In front of all that, there is an elaborately constructed carbon fiber crash bar that can handle huge amounts of impact, after which its disposable cones crumble into dust as the impact progresses. At the rear, there is an all-aluminum independent suspension system that looks like it was ripped directly out of a racing car. No other car in the world is built quite like this one, and it is as beautiful underneath as it is brutish on the outside. The only major panels shared with the coupe are the scissor doors.

The 626-horsepower 5.5-liter supercharged V8 engine nestles under the long, long hood, breathing directly through the Mercedes-Benz star in the nose of the car, and exhausting through a compact, front-mounted exhaust system that exits through the bottom edges of the front fenders. This does three things. It works very well for emissions, keeping the catalytic converters hot. It helps the engine breathe better at higher rpm. It eliminates a lot of pipes and mufflers under the car, which has a flat bottom for aerodynamic purity. Oh, and four, it puts the sound of that V8 engine very close to the cockpit, where it can be appreciated. Read on to our Driving Impressions to see what we thought of all this.