The range-topping CLS was spotted at the Nürburgring where AMG was testing two prototypes.

Heralding a new lineup of hot cars from Mercedes-AMG, the CLS 53 was originally unveiled back in January at the North American International Auto Show in Detroit. It was then later brought to the Geneva Motor Show in March for its European debut and now the hybridized stylish sedan has traveled to the Nürburgring for some last-minute adjustments. Two prototypes of the flagship CLS model were seen at the track, with the gray one featuring a roll cage in the back you obviously won’t be able to order on the production model.

The CLS 53 is being joined in Mercedes’ vast lineup by a quartet of 53-badged models from the E-Class: sedan, wagon, coupe, and cabriolet. These are all sharing the same hybrid powertrain consisting of a turbocharged inline-six 3.0-liter gasoline unit and an electric motor. With the power of the two combined, the CLS 53 develops 429 horsepower (320 kilowatts) and 384 pound-feet (520 Newton-meters) of torque. All that hybrid punch is channeled to the 4Matic+ variable all-wheel-drive system through a nine-speed automatic transmission.

In the case of the CLS 53, the sprint to 62 mph (100 kph) takes four and a half seconds, which is not too shabby considering the stylish sedan weighs a hefty 1,905 kilograms (4,200 pounds) in European guise, without a driver. Flat out, it will do an electronically governed 155 mph (250 kph) or 168 mph (270 kph) if you fork out more money for the optional AMG Driver’s Package.

The attached video not only gives us the chance to see the CLS 53 in action without any camo, but it’s also an opportunity to hear the interesting soundtrack provided by its intricate powertrain. Those new quad rounded exhaust tips are a signature of the 53-badged cars, as are the additional side air curtains reducing the swoopy sedan’s drag coefficient.

Although these two prototypes did not have it, the final production car also features a rear spoiler on the trunk lid to further separate it from the lesser CLS versions. Customers will be able to get it in the same color as the body or in optional carbon fiber.

Mercedes-AMG will have the CLS 53 on sale in Europe in the coming weeks before bringing it to the U.S. this fall.

Video: Automotive Mike / YouTube

Gallery: 2019 Mercedes-AMG CLS53