SANTA MONICA, California — It won't make its official debut until this summer, but the Mercedes-Benz SL65 AMG Black Series is already staking its claim as one of the most extreme Mercedes-Benzes ever built.

It starts with a 6.0-liter twin turbo V12 engine. In the standard SL65 AMG it pumps out a healthy 604 horsepower, but in the Black Series the same engine gets cranked up to 670 hp. The torque peak won't increase, but given that it already sits at 738 pound-feet, there's really isn't a need for more. The five-speed automatic transmission, torque converter and all, will remain, but it will get two Sport shift programs, with the second delivering quicker gearchanges timed at just 250 milliseconds.

In addition to the added power, the engineers at Mercedes-Benz concentrated on reducing the car's weight. AMG's engineers chucked the heavy airbag suspension setup on the standard SL65 for steel coil springs, lost the Active Body Control system and made the Black's trunk, vented hood, roof, vented front fenders and bumpers out of carbon fiber.

Weight savings also turned the car into a coupe. Instead of a heavy folding hardtop, the Black Series gets a fixed roof fortified with a fully integrated roll cage. The changes reduce the car's overall weight by 570 pounds and give it a power-to-weight ratio of 1 horsepower per 6.1 pounds.

During a sneak peak of the car during the 2008 New York Auto Show, Thomas Rappel, the CEO of AMG, also told us that the folding roof was also nixed because it didn't fit between the Black's massive 325/30ZR20 rear tires. The sharp-eyed will also notice that the SL65 Black is 5-10 inches wider (AMG wouldn't tell us exactly how wide) than a drop-top SL and its roof line is now longer. "We wanted it to look more like a proper coupe," Rappel said during a tour of the car.

The brakes and steering system are identical to those found in the Performance Package offered on the recently introduced SL63 AMG. One noticeable change will be the wheel and tires package. Dunlop SP Sport Maxx GT tires will be fitted, and the front tires measure "only" 265/35ZR19s. The Black will also get two suspension settings which we'd bet are stiff and stiffer.

It all adds up to a coupe that will be able to go from zero to 60 mph in less than 4.0 seconds and have a top speed of 198 mph. A retractable spoiler will help to generate 77 pounds of downforce above 60 mph, which is the speed it magically rises from the deck lid.

Interior changes are minimal. It will get the same AMG seats as the standard model (the carbon seats have no side airbags so they won't make it into U.S.-spec cars) along with a flat-bottom steering wheel, an Alcantara headliner and a navigation system. Black will be the only interior color offered, and the carbon-fiber trim on the door panels and console is appropriate. The projected price is more than $225,000 and there will be no options. Expect to see the official unveil this summer, with sales starting this fall. Only 350 units will be built.

"We strive to supply American customers with what they want," Rappel told us. "And in this case what they want is performance."

What this means to you: The Corvette ZR1 is extreme. The SL65 AMG Black Series is downright ridiculous. You want one and you know it. — Scott Oldham, Inside Line Editor in Chief