The 600LT is the third model in the McLaren Automotive era to receive the Longtail treatment, after the 675LT and its Spider counterpart.

We’ve driven the car on track at the Hungaroring near Budapest already, but with no road element on that particular event, we were left guessing how the car would perform away from a grand prix circuit. Until now.

Longtail is to McLaren what RS is to Porsche. The 600LT belongs to the entry-level Sports Series family and has been re-engineered to be faster, lighter, more agile and more exciting than the already brilliant 570S that it is derived from. Reduced weight, optimised aero, more power, track-focused dynamics, driver engagement and exclusivity are the core Longtail attributes, says McLaren.

To give you an idea of where it has tried to pitch the 600LT, the rival cars it speaks of in its press literature are the Porsche 911 GT2 RS, the Lamborghini Huracán Performante and the Ferrari 488 GTB (not the much more powerful 488 Pista, notably).

How has McLaren saved weight on the 600LT?

Tick every lightweight option box and your 600LT will come in at 1247kg dry, which is 100kg less than a 570S. Beware, however, that by pursuing the lowest kerb weight possible, you will configure a car with no air conditioning, no stereo and no front axle lift, and with ultra-lightweight seats from the Senna hypercar that will distort your spine and numb your legs over very long journeys. This particular test car was so configured (although it did have the axle lift).

Weight has been cut elsewhere through the use of thinner glass, carbonfibre for more of the body panels, top exit exhausts that have less pipework and lightened suspension components.

The 600LT’s rear end stretches 47mm further back than the rear of a 570S, which is how McLaren justifies the Longtail nomenclature. You will need to be very familiar with McLaren’s model range to recognise that in person, but the one-piece carbonfibre rear diffuser and bumper assembly is not at all difficult to spot.

Whereas a 570S is lift neutral at 155mph, the 600LT actually produces 100kg of downforce, thanks to an aggressive front splitter and new side skirts, that prominent diffuser and a fairly modest rear wing.