2014 Mercedes-Benz SL63 AMG

The Mercedes-Benz SL63 AMG is a hardtop convertible that seeks to strike an ideal balance between prodigious performance and coddling luxury. The SL63 boasts up to 557 horsepower in addition to an impressive 275 lbs. weight reduction compared with its predecessor.

The SL63 AMG slots between the standard SL550 and the upcoming V12-powered SL65 AMG in Mercedes' SL-Class lineup.

SL is short for sport leitch, or sport lightweight in English, and Mercedes-Benz went to great lengths to pare mass from the new car to help it live up to its name. Underneath the sheetmetal is a low-weight aluminum bodyshell not unlike that used in the SLS AMG supercar. High-strength steel is incorporated at key points to enhance rigidity, but the car is primarily constructed of lightweight aluminum. Carbon fiber composite used on the trunk lid's inner frame also helps to trims weight. The result of all the weight-saving measures is a mass of just over 4,000 lbs.

To stand apart from the SL550, the SL63 AMG gains its own unique body kit and AMG-specific LED running lamps. Special V8 Biturbo badging hints at what provides motivation. At the rear, a small spoiler lip improves aerodynamics and stability, while a sport exhaust system exits through a unique diffuser.

Inside, the SL63 AMG gains the requisite sports seats and steering wheel that mark other products modified by Mercedes-Benz's performance arm. The Magic Sky Control panoramic glass roof that shows up in the standard SL is similarly optional in the SL63; at the press of a button, the glass roof's tinting can be changed from light to dark.

Underhood Motivation
Although more of a high-performance grand-tourer than an all-out sports car, the SL63 AMG still boasts impressive power in addition to relatively deft backroad moves.

The SL63 uses the same 5.5-liter V8 engine used in many other AMG products. Boosted by a twin turbochargers, the V8 cranks out 530 horsepower and 590 lb-ft. of torque in its standard configuration. But buyers interested in outright speed can select the AMG Performance Package, which ups those figures to 557 ponies and 664 lb-ft. of torque.

The AMG Performance Package-equipped SL63 sprints to 60 mph in just 4.1 seconds before topping out at an electronically-limited 186 mph. Despite all that power, Mercedes-Benz says that fuel economy is up 30 percent compared with the previous engine, although specific figures will have to wait until closer to the car's launch later this year.

The V8 uses an eco start/stop system to further save fuel, while its seven-speed automatic transmission delivers power to the rear wheels. An AMG-modified active sports suspension ensures improved handling over the standard SL roadster, but a Sport button can be engaged to select even firmer shock danmping to reduce body roll. Electro-mechanical power steering has been specially tuned for a faster ratio than the standard SL.

The standard AMG-modified brakes can be further upgraded with the selection of the AMG Performance Package, which includes 15/3/14.2-inch disc brakes and ceramic pads. Standard wheels are 19-inch AMG models, but the Performance Package staggers things with a 19/20-inch front/rear setup.

Standard and Optional Luxury Features
The SL63 AMG comes well-equipped with a long list of standard kit, including premium AMG leather upholstery, a harman/kardon Logic7 audio system with Mercedes-Benz's Frontbass acoustic champers, a navigation system with a 40 GB hard-drive and Sirius XM real-time traffic info, Bluetooth smartphone connectivity, voice command capability for audio, phone and nav, a panorama roof, dual-zone automatic climate control, a power wind blocker for high speed top down motoring.

Those looking for more luxury can opt for the Premium 1 Package, which adds a smartkey, PARKTRONIC with active park assist, heated and ventilated seats, MercedesïÃ'¿Ã'½ AIRSCARF neck-level heating system, a power trunk closer, a rear view camera and active multicontour seats.

A number of stand-alone options are also available. Highlights include carbon ceramic brakes, a Bang & Olufsen surround sound system and special 10-spoke 20-inch wheels.

Occupant Safety
In addition to traction and stability control systems, the SL63 AMG boasts six supplemental restraints including two-stage front airbags, dual knee airbags and dual side airbags. Roll over hoops mounted behind the seats provide an extra measure of protection.

Also standard is an ïÃ'¿Ã'½ATTENTION ASSISTïÃ'¿Ã'½ system that can alert the driver to the first signs of drowsiness, a factor that causes more than 100,000 accidents a year in the U.S.A steering sensor is coupled to smart software that uses 70 parameters to establish a unique driver profile during the first 20 minutes of driving. Between 50 and 112 mph, the system identifies the erratic steering corrections drivers make as they begin to get drowsy and triggers an audible warning and a "Time for a Rest?" message with a coffee cup icon in the instrument cluster.

Optional safety equipment includes the Lane Keeping Assist system, which alerts the driver by simulating a rumble strip vibration in the steering wheel if the car drifts from its lane without the turn signals on. Part of the Driver Assistance Package, it operates at speeds above 37 mph via a system that recognizes lane markings, thanks to a small camera in the windshield and a computer that analyzes the video images.

The Driver Assistance also includes radar-based cruise control in addition to Blind Spot Assist, which monitors both blind spots behind and to the side of the vehicle. Whenever a turn signal is activated with a vehicle in the blind spot, the driver gets visual and audible warnings.

Key Competitors
Those in the market for a powerful roadster that's also a comfortable highway cruiser should also consider alternatives to the SL63 AMG like the Jaguar XKR Convertible, the Maserati GranTurismo Convertible Sport and the Porsche 911 Carrera S Cabriolet.