The Mercedes-Benz SL65 AMG Black Series (www.mbusa.com) might represent the last hurrah for the current-generation SL. If this is so, the class is not going quietly. When the SL65 is at full acceleration, on its way from zero to 60 mph in 3.8 seconds, the air intake of its twin turbochargers produces a harrowing whoosh. The performance of the AMG Black (as the car is known at the AMG plant) is as menacing as the vehicle’s low-slung profile and flared carbon-fiber front body panels suggest: 661 hp at 5,400 rpm, 738 ft lbs of torque at 2,200 rpm, and an electronically limited top speed of 199 mph. Equally arresting are the car’s price and production figures: The SL65 AMG Black Series costs $304,000, and Mercedes-Benz plans to deliver only 175 examples to the United States.