Spied: 2018 BMW M5

The next M5 will boast more power and optional AWD.

BMW's next-generation 5-Series is still a few months away from its first public unveiling, but engineers at the German automaker have already begun work on the line's high-performance M5 variant.

Seen here testing near the Mojave Desert, it's clear that the shape of the next-generation 5-Series won't change much compared to its current form. Likewise, this M5 variant looks to stick to the theme of evolution rather than evolution.

However, changes are afoot beneath that familiar exterior. The next M5 will retain a twin-turbocharged 4.4L V8, but it's believed that power will be bumped from today's 560 horsepower up to 626 horsepower. That engine will have less weight to haul around too, thanks to a new platform that is expected to shed about 220 pounds compared to today's model.

In order to keep up with the Mercedes-AMG E63, the new M5, likely to be branded as a 2018 model, will offer an optional xDrive all-wheel drive system. Buyers will, however, still be able to order their M5 with rear-wheel drive.

As a result of that new hardware the new M5 should be capable of ripping from 0-60 in the mid-three-second range. That blast will be a little less engaging this time around, however, as BMW will likely drop the M5's slow-selling manual transmission option.

Interestingly, we've heard reports that BMW is strongly considering a wagon-version of the next M5 to take on the Audi RS6 Avant and Mercedes E63 Estate. However, it's doubtful that such a model would make it to these shores.

With the standard BMW 5-Series tipped for a debut later this year, it might not be until late 2017 or early 2018 until we get to lay eyes on the new M5.

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