The Mercedes-Benz GT AMG, the firm's new 500bhp-plus V8-powered sports car, has entered the final phase of testing. The public debut of the rear-wheel-drive coupé is planned for the Paris motor show in October.

The exclusive computer-generated rendering shown above is based on recent spy photographs of the aluminium-bodied two-seater running at the Nürburgring circuit. The new Mercedes-Benz, which goes under the codename ‘C190’, is set to go on sale 
in the UK next April.

The new GT will be priced to compete directly against the likes of the Aston Martin V8 Vantage and Porsche 911 Carrera S, at about £100,000 - a considerable £70,000 less than the outgoing SLS.

The GT indirectly replaces the SLS at the very top of the Mercedes-Benz line-up, where it will act as a styling and performance figurehead for the rest of the German car maker’s line-up.

The more highly positioned and highly priced SLS is being produced in a limited five-year programme that is due to end in May. The GT, meanwhile, is scheduled to be produced over a six-year period through to 2020, at which time Mercedes-Benz plans to resurrect the SLS on an all-new carbonfibre-intensive platform structure.

At launch, the GT will offer close to 520bhp, giving it a clear power advantage over both the V8 Vantage (420bhp) and 911 Carrera S (395bhp). However, there are also plans to launch a milder version with about 480bhp in 2016. Also in the pipeline, but not planned to see the light of day until 2018, is a track-focused GT Black Series model that is set to pack up to 580bhp, according to high-ranking AMG insiders.

The basis for the GT is a modified version of the SLS’s aluminium body structure. Manufactured by Magna in Graz, Austria, it has been extensively reworked for the new two-seater. Initial reports suggest that the GT has a kerb weight of about 1480kg, some 140kg less than the SLS coupé.

Mercedes-Benz’s head of design, Gorden Wagener, has closely overseen the styling of the new car. He has described the GT as being much more contemporary in appearance than the SLS, with sharper detailing, tauter surfacing treatment and a generally more structured look that 
will influence the styling of other future Mercedes-Benz models. “It makes the SLS look dated,” he said.

The overall proportions of the GT are very similar to those of the SLS, with a long, probing nose, a cabin set well back within the wheelbase and a stubby rear. The intention is to provide clear links with some of Mercedes-Benz’s most revered sports cars. 

Dimensionally, the GT and SLS are very similar. Nothing is official, but insiders have indicated that the GT will run close to the 4640mm length, 1940mm width and 1260mm height of the SLS.  

However, there are clear differences between the two. Eschewing the heavy gullwing doors of the SLS, the GT has more conventional front-hinged doors in a move that is claimed to both streamline assembly and provide the new car with a significantly lower centre of gravity thanks to a much lighter roof structure.

A further significant change is the adoption of a liftback-style tailgate in place of the boot used by the SLS. The new layout, a first on a Mercedes sports car, is aimed at boosting everyday practicality.

Unlike the SLS, which is made in coupé and roadster body styles, the GT is set to be produced exclusively as a coupé. “There was some initial thoughts about doing a roadster variant but, at this stage, there are no plans to do an open-top version,” a senior source revealed to Autocar. “We have the SL to fill that role.”

Inside, there is a snug two-seat interior with a layout that, Wagener said, has been heavily influenced by aircraft cabin design. The dashboard progresses the look and layout seen on the SLS with a combination of bespoke instruments and controls taken from other Mercedes-Benz models, most notably those of the new C-class.  

The GT will be the first Mercedes-Benz model to 
be powered by AMG’s new twin-turbocharged 4.0-litre V8 petrol engine, the ‘M177’, 
as it is codenamed. The aluminium unit is also scheduled to be used in the successor to the C63 AMG. 

The new V8 shares its modular construction, including 90mm bore centre spacing, with AMG’s ‘M133’ turbocharged 2.0-litre, 
four-cylinder engine, which powers the A45, CLA45 and recently introduced GLA45.

Details remain scarce, but sources close to the German car maker say that it will support a number of different outputs, ranging from 480bhp to more than 580bhp. The initial model is set to offer about 520bhp - some 50bhp less than the naturally aspirated 6.2-litre V8 used by the SLS. But with forced induction helping to swell reserves at lower revs, the new engine is set to produce  considerably more torque 
than the SLS’s 415lb ft.

Power goes through a seven-speed dual-clutch automatic gearbox mounted within the rear axle assembly. The Getrag-produced unit is carried over from the SLS but upgraded with new electronic mapping and other unspecified changes, providing what one AMG insider has described to Autocar as “faster and smoother operation under all conditions”. Also included is a mechanical locking differential and the latest electronically controlled torque vectoring.

The GT will be assembled at AMG’s Affalterbach factory in Germany. Mercedes hasn’t divulged expected volumes, 
but officials are confident that the GT will sell in higher numbers than the SLS.