It seems that the Mercedes-Benz AMG GT Black Series has taken the Nürburgring lap record as per youtuber Micha Charoudin states. The 6:43 time, a full second faster than the SVJ which did it in 6:44.97. The alleged 6:43 time is based off of Misha’s speculation and calculations, granted he specializes in Nürburgring content for YouTube.
The most extreme car in Mercedes-AMG’s current lineup, the $389,000 Black Series GT uses a 4.0-liter, flat-plane crank, bi-turbo V8 sending power exclusively to the rear wheels.
The article from The Drive goes more in depth with the topic.