That's up by 40 horsepower compared to a normal M5.
While the attached video may be all about the recently introduced M5 loaded with M Performance Parts on display at SEMA, it appears to contain a tasty Easter egg if you pause at the 0:29 mark. Posted by BMW USA on its official Facebook account, the clip shows the digital horsepower gauge on the infotainment’s screen going all the way up to a maximum 640 horsepower. As a refresher, the regular M5 tops out at 600 hp, which likely means the extra 40 hp will be offered with the already announced Competition Package.
That being said, the old M5 (F10) also had the Sport Displays showing 640 hp without the car actually offering that kind of power, but it's interesting the promo video briefly focuses on the horsepower gauge.
Although we can’t see the torque dial in full, chances are the beefier M5 will come with a minor bump over the 553 pound-feet (750 Newton-meters) available in the standard car. This output hike is slated to arrive most likely sometime next year along with other hardware upgrades, such as ceramic brakes and a more track-oriented setup for the chassis. Other changes in tow include a stiffer suspension bringing a lowered ride height, together with bespoke wheels and sharper handling.
These improvements should make the all-wheel-drive machine even quicker than the normal M5, so expect the sprint to 62 mph (100 kph) to take slightly less than the current 3.4 seconds. Top speed will certainly be at least the 189 mph (305 kph) achieved by the regular version when configured with the usual optional M Driver's Package offered by BMW for its M models.
The latest M5 will go on sale in the United States from March 2018 and will be available from day one with a generous array of M Performance parts. The Competition Package bringing an uprated biturbo 4.4-liter V8 engine could arrive before the end of the year to rival the Mercedes-AMG E63 S.