The 620R carries the 570S GT4's bodywork and aerodynamics with a number plate attached. It is a race car brought back to the road rather than a road car sent to the track, and McLaren built 350 of them.

The engine is the 3.8-liter twin-turbo V8 with new turbochargers and a recalibrated ECU, and the number in the name covers both outputs: 620 horsepower and 620 Nm. A strengthened driveline handles it, through a seven-speed dual-clutch to the rear wheels, making this the most powerful car of the Sports Series. Dry weight is 1,282 kg. 0 to 100 km/h takes 2.9 seconds, 200 km/h takes 8.1 seconds, and top speed is 322 km/h.

The adjustable carbon fiber rear wing is the GT4's own, and the giveaway is the third brake light built into it, which is there so the car could be registered. At its steepest setting it generates 185 kg of downforce.

The dampers are two-way adjustable motorsport units with 32 settings, so the car can be set up for a circuit and then set back again. Carbon-ceramic brakes and Pirelli P Zero Trofeo R tires are standard rather than optional.

Inside, the air conditioning and the infotainment system were taken out to save weight. Both could be put back at no cost, which tells you how the car was meant to be ordered.