M850i not enough? You'll have to wait for this full-fat M model.

BMW aficionados know their favourite brand built an M8 prototype nearly 30 years ago, which never evolved to become a production model. As a matter of fact, the car was kept secret for many years before being unveiled to the public. Now, the Bavarians are putting the finishing touches on an M8 deep-pocketed people will actually be able to buy. Even better, the coupe will be joined sooner or later by a convertible and eventually by a four-door version to serve as a successor for the M6 Gran Coupe.

Seen here is the two-door flavour with the fixed roof while being pushed hard at the Nürburgring where it’s currently undergoing final testing. Set to be positioned atop the M850i, the crown jewel of the reborn 8 Series family will use an amped-up version of the biturbo 4.4-litre V8 expected to produce more than 600 brake horsepower. Considering the recently launched M5 Competition packs a mighty 617 bhp punch, we won’t be too surprised if the M8 will top that. A possible M8 Competition could have even more.

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There’s a pretty good chance the xDrive all-wheel drive layout and the eight-speed automatic transmission will be adapted from the M5. An assortment of upgrades over the M850i is also in the works and BMW could shave off some fat here and there to bolster performance. Even if a diet is on the agenda, don’t expect the M8 to be a lightweight coupe considering the U.S.-spec M850i tips the scales at a rather hefty 2,031 kilograms.

BMW has already confirmed it will unveil the M8 later in 2018, so we might get to see it at the Paris Motor Show in October or even a couple of weeks sooner on the Internet. The other two 8 Series body styles we’ve mentioned earlier will also be blessed with the full-on M treatment.

Video: Automotive Mike / YouTube

Gallery: BMW M8 Coupe spied at the Nurburgring