There is absolutely no reason why any two-seat roadster should be fitted with a twin-turbocharged 6.0-liter V12 developing 621 horsepower and 738 pound-feet of torque, but I sure am glad that Mercedes-Benz doesn't see things that way.
Drop into the leather-lined cockpit of this $213,145 provocateur, floor the accelerator pedal as I did over and over again, and 60 miles per hour falls in a traction-limited 3.9 seconds. Top speed has been electronically held to 186 mph (this apparently saves Gulfstream jet owners from embarrassment). Forget the SL550 and SL63 AMG, the valets will trip over themselves attending to the tycoon driving this thoroughbred – it's the real deal.
- The handcrafted 36-valve V12 returns with a new internal designation of M279 (replacing the M275) and a matte carbon-fiber engine cover. Mercedes-Benz has updated the powerplant's turbochargers and improved engine airflow for the 2013 model year. This explains the 17-horsepower improvement and efficiency gains over its predecessor. The venerable five-speed automatic was also replaced with AMG's Speedshift seven-speed transmission (offering electronically controlled Efficiency, Sport, Sport Plus and Manual modes), and the SL65 AMG now features an engine start-stop function.
- Acceleration rates normally flatten as aerodynamic drag rises. The SL65 AMG seems to do just the opposite as it picks up speed like a rocket leaving the earth's pull of gravity. Full throttle applications release a throaty growl from the quad exhaust, accompanied by spine-chilling burbles as the transmission catches each gear. Downshifts are equally as pleasing as the V12 cackles and pops as each gear falls. Yet, during steady cruising the exhaust note is perfectly tame and proper.
- Despite is substantial physical size, the SL65 AMG is surprisingly agile. It tracks well and the new electrically boosted steering is precise and nicely weighed. Cornering is flat, thanks to Active Body Control (offering both Sport and Comfort settings). The 19-inch wheel and upgraded monobloc brake package (lifted right off the enthusiast-tuned SL63 AMG), does its job commendably.
- The cabin is a smart mix of luxury and sport. What leather doesn't cover is made of either woven carbon-fiber or brushed aluminum. The infinitely adjustable quilted seats are heated and equipped with the automaker's neck-heating Airscarf. The meaty three-spoke flat-bottom steering wheel is wrapped in smooth leather with grippy Alcantera sides and aluminum wheel-mounted paddle shifters are standard. The convertible hard top, with its lightweight magnesium frame encircling the automaker's trick Magic Sky Control dimming feature, can be raised or lowered in about 20 seconds at the touch of a button.
- Don't confuse the SLS AMG GT Roadster with the SL65 AMG, as each has very different role. The SLS is a true sports car, with a mission-appropriate ride, gnarly exhaust snarl and a moderate level of amenities. The SL65, on the other hand, is a luxury grand tourer engineered to make miles pass effortlessly beneath it chassis. One does not replace the other – a true boss owns both.