This is the Merc C-Class DR 520, an even-more-powerful, limited-edition version of the C63 AMG, named in honour of 1960s actress Diane Rigg.
That's not true. The DR 520 is actually named in honour of Dizzee Rascal, the British rapper, record producer and winner of the 2003 Mercury Prize.
That's also not true. The DR 520 is actually named in honour of 1970s Leeds and England manager Don Revie, who...
Oh, OK. DR 520 is actually short for ‘Dyno Rated 520'. Yes, that's the power output of this uprated C63: 520bhp, a full 60bhp more than the definitely-not-underpowered-in-any-way C63 AMG.
There's also an extra 37lb ft of torque, which stands at a tarmac-warping 479lb ft. In a C-Class, don't forget. In a C-Class.
As you may have predicted, it is fearsome quick. In saloon form, the DR 520 will devour the 0-62mph sprint in 4.1 seconds, with the estate just a tenth of a second behind. Both are electronically limited to 187mph, which is probably fast enough.
The DR 520 is available in matt black or white, and gets lots of AMG performance bits as standard. It costs £10,000 more than the standard C63 - not an entirely ridiculous price for a car that will happily destroy most supercars.
And rear tyres. Won't someone think of the rear tyres?