Wild GT4-based McLaren 620R leaked

An even faster, more extreme version of the McLaren 600LT has surfaced, capitalising on the car-maker's investment in GT4 racing.

The new road-legal McLaren 620R, revealed here in images leaked by Pistonheads, is set to be made in extremely small numbers for those who demand an even more track-focused version of the already hardcore 600LT.

carsales originally broke the news back in June 2018 that a faster GT4-inspired Sport Series McLaren was on the way when one of the car-maker's chief engineers, at the original reveal of the 600LT, let slip he was lobbying hard for a road-legal version of the race car.

Featuring a larger rear spoiler, front splitter, a set of anti-dive planes and a huge rear diffuser, the 620R features aerodynamics honed for the 570S GT4 racer.

The result is a 600LT-based road car that generates significantly more downforce and reduced lift at high speeds. The aero is also fully adjustable and can be set up for big downforce or low drag, depending on the circuit.

The 620R also sports a set of the racer's ultra-lightweight 18-inch wheels plus a roof-scoop cold air intake.

Disappointingly, since it's closely based on the GT4 car the 620R loses the 600LT's cool flame-spitting top pipes for a pair of conventional rear exit exhausts.

Sitting lower to the ground, the fastest-ever McLaren Sport Series gets a full GT4-derived suspension set-up with bespoke adjustable dampers.

Both carbon-ceramic brakes and a new cut slick road tyre are also expected.

Inside, the 620R misses out on a full roll cage but gets full carbon-fibre race seats, a six-point race harness and full track telemetry accessed through the infotainment system.

The engine powering the 620R does without the 570S GT4 race car's restrictor, which limits power to 419kW. Instead, the twin-turbocharged 3.8-litre V8 produces 620hp (456kW) – 15kW more than the 600LT. A small bump in torque, over the 620Nm the standard car produces, is also expected.

Full performance details have yet to be revealed, but it's thought the 620R will be fractionally lighter than the 600LT.

According to the British car blog, the special 620R is only available to 'select' McLaren customers that have been invited to purchase it, hinting at a substantial premium over the $455,000 (plus on-roads) the British supercar maker already charges for the coupe.

Due to its track-focused nature, a 620R Spider is unlikely to be in the pipeline.