The new SL63 AMG offers the best combination of power and handling. It is a meaner version of the SL550 in terms of power and is even better when it comes to handling. It cranks out 518 horsepower at 6800 rpm and 465 pound-feet of torque at 5200 rpm. The SL63's 6.2-liter V8 barks like the biggest dog on the block at startup, under acceleration and during downshifts, and emits a constant background rumble while cruising. A freer revving engine, the 6.2 hits its redline at 7200 rpm, which is pretty high for a large V8. It comes with a new seven-speed automated manual transmission that Mercedes calls the Sportshift MCT 7. MCT stands for Multi Clutch Technology, and the multiple clutches allow this transmission to shift gears with no interruption in power delivery. The new AMG transmission has four driving modes, Comfort, Sport, Sport-Plus and Manual. Sport shifts 20 percent faster than Comfort, Sport Plus shifts 20 percent faster than Sport, and Manual shifts another 10 percent faster than Sport Plus, or 50 percent faster than Comfort. In Manual, shifts take only 100 milliseconds. The MCT also features multiple downshifts, from seventh to fourth or fifth to second, for example, with double-clutching, throttle blipping and perfect rev-matching in between; the Sport Plus program works like a skilled driver might to keep the engine in the power band for hard driving. It downshifts readily when you get off the gas, such as in a long sweeping turns, so maximum torque is on tap when you're ready for the power again. Mercedes quotes a 4.4-second 0-60 time for the SL63, and we believe it.
The SL65 AMG has a twin-turbocharged V12 that makes an astounding 604 horsepower from 4800-5100 rpm and a stump-pulling 738 pound-feet of torque from 2000-4000 rpm. Like the SL600, it is more subtle about its performance capabilities, issuing a subdued turbine-like hum. The SL65's 0-60 mph time is 4.2 seconds, and it feels even quicker. With just a 0.2-second difference in 0-60 times, you might think there wouldn't be much difference between the SL63 and the SL65. You'd be wrong. While the SL63 is a grunty, torquey beast, the SL65 delivers a rush of power that throws you back into your seat and feels like a jet taking off. It also has an unfortunate tendency to sta Next Page