This is a tuned Mercedes-AMG GT 4-Door

This snappily titled thing is the Performmaster Mercedes-AMG GT 63 S 4-door Coupe 1 of 31 Limited Customer Edition. Got your breath back yet? Well, the 731bhp this thing puts out will probably take it away all over again. 

Now, with 631bhp on tap, the standard GT 63 S 4-door is not exactly short on power. However, all it takes to squeeze out the extra ton is a bit of electronic trickery in the form of a PEC tuning module from the AMG specialists at Performmaster.

When connected to the 4.0-litre twin-turbo V8, the module also ups torque from the standard 664lb ft to a rather obscene 760lb ft (or over 1,000Nm if you’re on the continent). 

The updates mean that 0-62mph is dispatched in just 2.9 seconds - outrageous in an internal combustion-powered saloon car - although top speed stays the same at a not paltry 196mph. Presumably so the monster Merc doesn’t shred its tyres thanks to a two-tonne plus kerb weight.

On the outside the upgrades are surprisingly subtle compared to what we’ve become used to seeing from German tuners. In fact, the only addition is a neat aero package that adds a front splitter, rear diffuser and ever-so-slightly larger rear wing to alert those in the know that this thing has more power than the bonkers Ferrari 488 Pista.

As the name suggests, Performmaster will limit production to just 31 cars to honour their 31 years of fettling AMG products. Want one? You’ll have to get behind us in the queue.