When BMW updated the M4 for the 2018 model year, output was increased by a measly six horsepower to a new total of 431 horses, and it looks like the Germans could make up for that with a more extreme version of the M4 GTS. Our paparazzi spotted a new GTS prototype on the Nurburgring, and it looks as if BMW built a more aggressive aerodynamic package.

The coupe that BMW launched in 2016 went through a series of significant changes on the outside. Up front, the bumper was given a bigger splitter and larger canards on the sides, while the profile showcases new air outlets and a louvered opening on the front fenders. The side skirts are also bigger, and it seems that the car sits closer to the ground.

The rear looks even more extreme thanks to a race-spec diffuser, an updated trunk lid spoiler, and a wing that sits higher than the previous unit. The "M4 GTS" badge and the production wheels suggest that this is indeed an updated version of the street-legal coupe, but BMW could also try to hide a motorsport version of the car. If this is indeed an upcoming road-legal coupe, we'll be getting a real track monster.

There's no hint as to what lurks under the hood, but the coupe should get its juice from an updated version of the companies twin-turbo, 3.0-liter, inline-six. The mill cranks out an impressive 493 horsepower and 443 pound-feet of torque in the old M4 GTS and logic dictates that it will get more oomph. However, don't expect more than around 20 horsepower and 15 pound-feet of twist. The good news, though, is that output will jump past the 500-horsepower mark, making this coupe the most powerful M3/M4 model yet.

The previous M4 GTS was the quickest Bimmer around the Nurburgring with a lap time of 7:28 minutes, so expect the updated model to improve that benchmark.

Further reading

Read our full review on the 2016 BMW M4 GTS.

Read our full review on the 2018 BMW M4.

Read more BMW news.