One: that is the tachometer of a two-ton Mercedes-Benz CLS and it's not on a dyno.
Two: the owner of the car is the same guy who found the Brabus Bullit to be slower than expected upon delivery.
What you (will try to) see in the video is a naught to about 220 km/h (137 mph) sprint in a Mercedes-Benz CLS 63 AMG tuned by the peeps at GAD Motors.
By “tuned” we mean that instead of the original 557 hp and 800 Nm (590 lb ft), its M157 twin-turbo V8 now delivers about 800 hp and 1150 Nm (847 lb ft). Not only that, but the original rwd car has been converted by the same GAD Motors specialists to 4Matic all-wheel drive, just like the 2014 option for the E and CLS 63 AMG.
The car hasn't been officially tested for acceleration and/or top speed, but just by seeing the way its speedometer moves we can guess it's one of the fastest CLS's in the world, if not the fastest. As soon as we find more info about the car we'll keep you posted, until then check out the “regular”, rwd, CLS 63 AMG by GAD Motors in the gallery bellow - which we covered, by the way, when it was released.