Hands up, we may have been a little cynical about the 675LT. There was a

camouflaged car

, a wheel, the camouflaged car again and

an exhaust

. We're used to McLaren drawing out a launch but this was silly...

Found the 650S a bit slow and chubby?

We were wrong. Very wrong. The Longtail is very much more than a

650S

with another 25hp, instead McLaren's version of a lighter, louder, stripped out track, um, special. Both that 458 and the new

488 GTB

will be cars McLaren wants to beat subjectively and on numbers. Neither is getting an easy ride given the spec.

The 25hp gain may look insignificant but in fact 50 per cent of the 3.8-litre twin-turbo V8 is new. The turbos are more efficient, the conrods are lighter, the heads and exhaust manifolds are upgraded and the the fuel pump is faster flowing. McLaren says driveability is up along with power and torque (now 516lb ft from 500) gains. Furthermore, the engine now has a new code (M838TL) as the tweaks were deemed that substantial.

The 'Longtail ethos' places a focus on light weight and optimised aero. To that end the 675 is 100kg lighter than a 650S through carbon body panels as well as "lightweight engine, chassis and body structure parts." The air-con has even been ditched (which probably accounts for a decent percentage of that 100kg) but can be optioned in at no extra cost. Then placed in the infotainment system, as if to punish your pathetic lack of commitment with unnecessary complexity.

Better aero performance key goal for LT

There's again a multitude of changes on the aero front. See the new front carbon splitter, front wing end plates and the new sills, there to ensure turbulent air from the front arches is 'cleaned' on its way to the rear bodywork. Right. Completing the lightweight aero upgrades are a bigger airbrake (made from carbon so it's lighter than on a 650S), carbon diffuser and that titanium exhaust. It saves 1.1kg, with the exposed sections flanking it to help hot air escape the engine.

Numbers? Incredible. 549hp per tonne means 0-62mph in 2.9 seconds, 0-124mph in 7.9 seconds (!) and 205mph all out. Plus 275g/km, in case you're interested.

To further distinguish the 675LT from a plain old McLaren Sports Series, it will be available in five 'hero specifications' with four colours never previously offered. So McLaren Orange is there, of course, alongside Silica White, Delta Red, Napier Green and Chicane Grey. Each will be matched to the interior materials and colours, with the most notable change inside being the inclusion of carbon-backed Alcantara bucket seats, modelled on those from the P1.