Short though the McLaren Automotive Longtail story has been - because the F1 GTR doesn't really count, does it - there's been an unerring consistency to the class of the finished product. The 650S was already very, very good; with weight stripped, power added and focus upped, it became the sublime 675LT - a car damn near as good as a Spider. Then the same happened with the Sports Series cars: the extremely impressive 570S becoming the borderline brilliant 600LT last year. Now there's the Spider version of that car, which, much like the 675, has only a small weight gain to speak of for its decapitation.
Compared to the 570S, the new model can be made up to 100kg lighter than the standard Spider. But the full three-figure saving requires some pretty serious commitment from buyers given that it requires them to forego air-con, nav and a stereo, and spec the MSO Clubsport Pack - different seats, more carbon inside, carbon front wing louvres and titanium wheel nuts - on top. Apparently, a few buyers are expected to go the whole hog, though the vast majority will keep those amenities in - a wise decision, surely.
With the roof mechanism carried over directly from the 570S, the 600LT Spider carries the same 50kg penalty over the coupe as all other Sports Series models. Fully lightened that means a dry weight of 1,297kg, admirably low (even allowing for another 20kg or so of air-con and radio added back in) when a 488 Spider is 1,420kg by the same measure. Otherwise, the intention has been to keep Spider as close to Coupe in terms of performance, with the same suspension tweaks - including an 8mm ride height reduction, stiffer, hollow anti-roll bars and recalibrated dampers - that featured in last year's car. Extensive aero work is said to have resulted in the same downforce as the hard top car, with 100kg delivered at 155mph.
As can probably be deduced from the pictures, the 600 was launched alongside the 720S Spider in Arizona. It's interesting to be able to compare the two almost back to back as well, and where Super Series surpasses Sports Series. The transition from hard top to retractable hard top is arguably more successful on the 720 (as you might expect given its £100k premium). The roof is faster and quieter, as well as being retractable at a higher speed, with a more cohesive profile top up or down. The 720 is more refined and easier to see out of as a Spider than the 600 is, as well as having a nicer interior. Certainly there's more of a gap in terms of experience as convertibles for these two than there is as coupes. If your aim is sun seeking, the Super Series does it more convincingly.
It should be noted, too, the tangible differences that there are between the two engines; while the M840T from the 720S has its origins in the earlier M838T (found in the 600LT), those changes ushered in have made a difference. As well as the stroked capacity, the 4.0-litre features new turbos, heads, pistons and crank over the 3.8-litre version. What that means on the road is a sharper, more energetic engine, one more eager to rev and more tuneful than the one which preceded it. To be honest, it's not something that's noticed until driving the pair in close proximity, though worth noting as a potential area of improvement for the Sports Series in time.
That criticism is worth noting early on because otherwise the 600LT Spider is pretty damn hard to fault. As cars - even ostensibly enthusiast-focused cars - seek to distance the driver from the what's going on around them, to drive something as immersive and as tactile as a 600LT is a rare privilege. Without ever being overwhelming or intimidating, it delivers everything in terms of clarity, response and feel that a keen driver would be looking for, in every area. It takes all that roadgoing McLarens have done so well and significantly ups the naughtiness - and without significant detriment to drivability.
What that means on Arizonian roads, be they concrete highways or snaking routes through the desert, is that driver will never forget that they're in a sports car; which would be a given if it weren't combined with the revelatory fact that they will likely never be annoyed by the constant reminder. In a similar vein to the Porsche GT models - and this is meant entirely as praise - there's an immediacy to the controls, a precision to the damping and a connection with the mechanical bits that means the Longtail experience always feels different to the regular McLaren one - more alive, more engaging, more intense. But never wearing.
'Normal' on the Active Dynamics panel for the chassis suits all road requirements, really - the additional damping authority of Sport not worth the trade off in comfort. Combine that with Sport or Track on the powertrain side - for as much drama from the V8 as possible - and the 600LT is manifestly superb, even on roads as featureless as those founds in Arizona. Longtails make other McLarens seem almost fuzzy, blobby and vague, which is saying something given the high bar already set. The steering is incisive and richly detailed, the agility unmatched and the brakes - with Senna tech, don't forget - beyond reproach. Those able to detect a discernible dynamic difference between Coupe and Spider on road would have to be in possession of a keener set of senses than this road tester.
The dynamic duplication extends to the racetrack, where the Longtail Spider delivers everything - absolutely everything - that made the Longtail Coupe such a stellar machine. There has to be a difference somewhere; there has to be, because 50kg is still 50kg, but it would take a back to back comparison - or rather, a back to back track pasting - to isolate it. To all intents and purposes, this 600LT behaves exactly like the last 600LT, which is to say superbly - only with more noise and more wind.
Whatever you wish to achieve on track, the McLaren is willing to accommodate. It'll hammer around fast and accurately all day long in its Track settings, bespoke Trofeo Rs and standard ceramic brakes lapping up - pun definitely intended - all the punishment that can be administered. Again the Porsche Motorsport comparison is valid, that same sense of integrity and stamina present here as in racy 911s. Vitally, however, there's real adjustability, balance and finesse to the LT's dynamic repertoire: it can be turned in and manipulated on the brakes like a hot hatch, line adjusted accurately off the throttle and immature oversteer fantasies indulged even with the persistent absence of a locking differential. The notes from the first set of laps read as follows: 'Rewarding, forgiving, engaging, tireless, fantastic', which sums up all you need to know about the 600LT track experience.
But it's not quite perfect. It's very, very close, but not quite. There are moments when the SSG gearbox doesn't deliver a downshift that was expected, and the engine, despite some welcome aural silliness on gearchanges, still sounds a little flat and lacks a bit in response when compared with its direct rivals. Yes, it's an oft-repeated concern, but when the competition includes the Huracan Performante Spyder, a car so musical it could headline a summer festival, it remains a valid one.
Beyond that, the McLaren 600LT Spider is a difficult car to criticise, and an extremely easy one to fall hopelessly in love with. Some may take issue with slightly sloppy infotainment and styling that arguably errs towards the garish. But as a driver's car the Longtail is utterly, utterly fabulous; just as it was for the Coupe, in fact, only now the roof comes down as well. What's not to love?
SPECIFICATION - MCLAREN 600LT SPIDER
Engine: 3,799cc, twin-turbo V8
Transmission: 7-speed dual-clutch auto (SSG), rear-wheel drive
Power (hp): 600@7,500rpm
Torque (lb ft): 457@5,500-6,500rpm
Top speed: 201mph (196mph roof down)
Weight: 1,406kg (DIN kerbweight, without driver)
CO2: 276g/km (WLTP)
Price: £201,500 (as standard; price as tested £244,880 including Elite Paint (Mayan Orange) for £3,660, By McLaren Alcantara LT interior for £1,950, Bowers & Wilkins 12-speaker Audio System for £3,640, McLaren Track Telemetry for £1,370, Soft Close Doors for £640, Power adjust steering column with comfort entry/exit for £1,420, Carbon Fibre Interior Upgrade Pack for £2,630, Lightweight Carbon Fibre Plenum Cover for £610, Gloss Visual Carbon Fibre Wheel Arches for £2,010, Dark Palladium Roof for £2,250, Gloss Visual Carbon Fibre Exterior Upgrade Pack 1 for £3,340 Gloss Visual Carbon Fibre Exterior Upgrade Pack 2 for £5,870, MSO Carbon Fibre Front Fenders with Gloss Finish Carbon Fibre Louvres for £9,960, Carbon Fibre Sill Finishers with McLaren Branding or £1,920, Glass Black Wheel Finish for £1,170 and Special Colour Brake Calipers for £940. And breathe...)