Spy shots and video clips of the 2021 Mercedes-AMG GT Black Series

The Mercedes-AMG GT has been updated for 2020, but a bigger, badder and possibly faster version of the Affalterbach-based tuner's only sports car being tested on some streets around the Nürburgring and German race tracks has been spotted.

The car appears to be a derivative of the track-oriented GT R Pro, but there are indications that this is a test driver of something even tougher. We're talking about the GT Black Series, which AMG boss Tobias Moers says will go on sale in 2020. This means it will likely be introduced as a 2021 model.

Black Series development isn't just about the power kit. Some readers may recall that the SLS AMG Black Series SLS had less torque than the standard model.

Presumably, we can expect less mass, a suspension designed for racing, and a correspondingly angular appearance (the huge grille is straight out of the latest racing version of the GT sports car). The aerodynamic elements also appear to have been refined to race car levels, as evidenced by the huge rear anti-wing and hood ducts.

The test car is also known to be equipped with a lightweight Plexiglas frame and rear glass. But the wheels are 19-inch front and 20-inch rear, with 285/35 front and 335/30 Michelin Pilot Sport Cup 2 rear.

Under the hood is the familiar 4.0-liter twin-turbo V8 engine. The current version of this engine produces 630 hp and 664 lb-ft in the GT four-door coupe, AMG's super sedan, making it the most powerful engine to date.

The GT R Pro has already clocked a time of 7:04.63, one of the fastest rear-wheel-drive production cars, but with only 577 hp and 516 lb-ft of torque, the GT Black Series is likely to clock under seven minutes on the circuit.

The car's primary target is Porsche's 911 GT2 RS; we wouldn't be surprised if the GT Black Series could compete with the flagship 911. Other potential targets include the Lamborghini Huracan Performante and the McLaren 600LT.

Stay tuned for updates as development progresses.