First look: Mercedes unveils bahn-storming SL63 AMG

AMG'S latest V8-powered creation has been unveiled in the shape of the Mercedes-Benz SL63 AMG ahead of its public debut at the Geneva motor show next month – a car that comes perilously close to matching the performance of its SLS AMG flagship stablemate.

The SL63 is pencilled in for a third quarter arrival in Australia – where AMG flagship variants account for 14 per cent of all SL sales.

Sharing the standard SL's lightweight aluminium-bodied construction – with a touch of carbon-fibre – the new SL63 is claimed to weigh 125kg less than its predecessor but will be available with up to 415kW of peak power and a tarmac-shredding 900Nm of torque, a significant boost over the outgoing SL63's 386kW and 630Nm.

Despite the weight loss, the presence of its trademark folding hard-top contributes to the SL63 weighing 225kg more than the SLS coupe and though the naturally-aspirated 6.2-litre V8 of the SLS produces 5kW more, its significantly lower 650Nm torque figure means the SL is likely to out-punch it in some performance areas, most likely mid-range acceleration.

In standard 395kW/800Nm trim, the 1845kg SL63 can achieve the 0-100km/h sprint in a claimed 4.3 seconds (three tenths quicker than the 1970kg outgoing model) using the standard 'race start' launch control system, meaning it matches the new BMW M6 convertible that will also debut at Geneva alongside its coupe counterpart.

A tenth is shaved off that time if the optional AMG Performance package is applied, matching the M6 coupe but still some way off the 1620kg SLS, which cracks three digits in 3.8 seconds.

Peak power for the SL63 is achieved at 5500rpm, while maximum torque is available between 2000rpm and 4500rpm for the standard car, with a narrower band of 2250-3750rpm for the AMG Performance package version.

In addition to the weight loss, AMG's downsized twin-turbo V8 engine with idle-stop is jointly responsible for a 30 per cent reduction in fuel consumption, from 13.9 litres per 100 kilometres in the old car to 9.9L100km in the new one.

What's more, the vastly improved fuel figure is achieved regardless of whether the engine is in 395kW standard or 415kW AMG Performance package tune – both of which provide significantly more performance – especially torque – than the outgoing unit.

AMG's 5.5-litre engine, in varying states of tune, also powers various other AMG-badged Benz flagship models, including the CLS and E-class (386kW/700Nm), CL-class (400kW/800Nm) and SLK (a naturally-aspirated 310kW/540Nm).

On the SL63, carbon-fibre has been applied to further reduce weight, the race-bred material used to form the inner support of the boot lid, where it is claimed to save five kilograms compared with a conventional design. Mercedes-Benz hints that the technology could filter into more products over time.

In addition to the agility advantages of reduced weight, the SL's aluminium body structure is more rigid, making it easier to tune suspension settings for a better ride/handling balance, reducing vibration and improving crash protection. Aluminium features heavily in suspension and steering components and some parts of the car are formed from even lighter magnesium metal, while high-strength steel tubes are used to reinforce the windscreen pillars.

The SL63 will come with Active Body Control sports suspension, switchable between sports or comfort modes, speed-sensitive steering and a Sport Handling mode for the electronic stability control.

Also switchable depending on driving style is the seven-speed automatic transmission, with economy, sport, sport plus and manual modes. The economy mode activates the engine's idle-stop system and softens gear changes, selecting a taller ratio at the first opportunity – including using the engine's considerable torque to pull away from stand-still in second gear.

The sport and manual modes work with the engine management system to briefly interrupt power delivery – but not revs – during full-bore gearshifts, claimed to produce an exciting sound from the exhaust, and the system also automatically blips the throttle on down-shifts.

Six-piston front brake callipers clamp 390mm compound rotors to bring the power and torque under control, with the rear 360mm rotors grabbed by single-piston items. AMG Performance package cars get the callipers painted red, while ceramic rotors for fade-free stopping power are optional.

Differentiating the SL63 from the rest of the range are twin-spoke 19-inch alloy wheels, a new radiator grille design with twin chrome horizontal bars, a redesigned front bumper with chrome lower lip, more aggressive side splitters, side vents and integrated LED daytime running lights.

At the back are a lip spoiler and quad exhaust outlets flanking a body-coloured diffuser-style rear apron.

Inside, the SL63 is inspired by the SLS – especially the styling of the centre console with its gearshifter and AMG drive mode selectors – plus jet engine-style air vents, AMG sports seats with AMG backrest badges, carbon-fibre trim, sports steering wheel and customised multi-function display with lap timer.

Standard equipment on the SL63 will include fatigue detection, six-CD audio system with Frontbass sound enhancement, remote-control power boot-lid, automatic headlights and wipers with adaptive windscreen cleaning system and a wind deflector.

Options include Airscarf neck heater, parking assistance, Bang & Olufsten or Harman Kardon premium sound systems and driver assistance technology including adaptive cruise control, radar-based automatic emergency braking, lane-keeping assist and blind-spot warning.

In addition to the extra 20kW and 100Nm provided by the AMG Performance package, the upgrade also includes a carbon-fibre engine cover, locking rear differential and a Nappa leather-covered performance steering wheel.

Pricing is yet to be announced, but the outgoing SL63 sells in Australia for $422,255, making it only $46,565 more affordable than the highly exclusive SLS AMG coupe.