Although we make every effort to cover our own travel costs, in this case McLaren flew us to Phoenix to drive the 720S Spider (and the 600LT Spider; we published that one last week) and provided two nights in a hotel.

In 2016, we tested the McLaren 650S Spider , a carbon-fiber drop-top supercar we thought was so clever it deserved a PhD. But three years is a long time in the supercar world, and the 650S is old news. Meet the McLaren 720S Spider. It, too, is made from carbon fiber. But now, instead of a 3.8L twin-turbo V8, there's a more powerful 4.0L twin-turbo V8. The car also has an all-new roof mechanism that goes up or down in just 11 seconds.

At the same time, the new model is lighter than the outgoing Spider (by 83lbs/38kg), making it the lightest car in its class (compared to the Ferrari Pista Spider, Lamborghini Huracan Performante Spyder, or the Lamborghini Aventador S Roadster). It's stupendously fast and extremely eye-catching—both qualities you'd want if you were spending $315,000 on a supercar. But it's also amazingly easy to drive, civilized to live with, and even pretty good on gas, considering it's capable of hitting 60mph in 2.8 seconds before topping out at 212mph (341km/h).

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

McLaren

McLaren

McLaren

McLaren

At the core of the 720S is its carbon-fiber tub. Called the MonoCage II-S, it's slightly different from the tub in the 720S coupe to accommodate the fact that the roof goes up and down. But there's no additional bracing or reinforcement to add any structural rigidity to the Spider, although it does have a pair of carbon-fiber rollover protection supports bonded to it (that also anchor the roof and the seatbelts). Compared to the tub in the 650S, it's easier to get in and out of thanks to lower sills, and it's easier to see out of, both front and back, thanks to slimmer A pillars and better rear visibility.

Because the 720S Spider is one of McLaren's mid-range Super Series models, it also gets carbon fiber body panels (as opposed to the steel and plastic ones used for the 570S , 570GT, and 600LT Sports Series cars). This gives the 720S Spider a dry weight of just 2,937lbs (1,332kg); for comparison, the 720S coupé weighs just 108lbs (49kg) more.

The styling may not be to everyone's tastes—I know when I first saw the 720S coupé and those headlights I wasn't a fan, but in the three paint hues McLaren brought to Arizona (Aztec gold, Belize Blue, and Supernova Silver, pictured), I find the front aspect a lot more palatable. From the sides and the rear, it's a knockout, at least to this author. At the rear, there's an active rear wing that now spans the width of the car. This performs a number of functions. It can raise up to add extra downforce, lie flat for reduced drag when accelerating in a straight line, or pop up as an airbrake under heavy braking to reduce stopping distances and improve stability. The wing adds 30 percent more downforce than the smaller one on the 650S Spider, and McLaren says that the new car is 30 percent better when it comes to aerodynamic efficiency (the ratio of lift:drag).

The 4.0L M840T engine is based on the 3.8L unit that powers almost all of the brand's other cars (with the exception of the Senna). The stroke has been increased by 0.14 inches (3.6mm) to increase capacity. Overall, McLaren says that 41 percent of the parts in the M840T are new compared to the M383T in the 650S, including but not limited to new turbochargers, intercoolers, plenum, cylinder heads, crankshaft, electronic waste gates, and lighter pistons. Peak power is 710hp (530kW) at 7,500rpm, with peak torque at 568lb-ft (770Nm) between 5,500-6,500rpm. (The rev limit is 8,100rpm in first gear and 8,200rpm otherwise.) As with all McLarens, power gets to the rear wheels via a seven-speed, dual-clutch "Seamless Shift Gearbox."

As you might imagine, with such little mass and so much power and torque, performance is blistering. From a standing start, you'll hit 60mph in 2.8 seconds, or 100km/h in 2.9 seconds. Zero to 124mph (200km/h) is dispatched in 7.9 seconds, and it will get to 186mph (300km/h) in 22.4 seconds. As mentioned earlier, top speed is 212mph (341km/h) with the roof up; with the top down, that's limited to 202mph (325km/h). Stopping power is similarly impressive, thanks to carbon ceramic brakes (15.4-inches/390mm front, 15-inch/381mm rear) and that active rear wing. Stopping from 62mph requires just 99.4 feet (30m) and happens in 2.8 seconds; at 124mph it will come to a complete stop in 4.6 seconds over 387 feet (118m). Those performance metrics are almost identical to the 720S coupé—it gives up 0.1 seconds to the slightly lighter hardtop in the run to 125mph and the quarter-mile (10.4 seconds vs 10.3 seconds) and a full second in the dash to 186mph.

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

Although people keep telling me that fuel consumption is unimportant to people buying $315,000 cars, I happen to believe some of them still care about the environment. For a car with more than 700 horsepower, it's actually quite good—the EPA rates it at 15/22/18mph city/highway/combined. After a day of hard driving, our test car reported just over 20mpg. McLaren says that the car that replaces the 720S will be a hybrid; in fact, it says the whole Super Series and Sports Series range will be hybridized by 2024. A battery-electric McLaren will have to wait for some battery weight breakthroughs, though.

But you could have learned all of this from reading McLaren's press kit. The reason we went to Arizona was to drive the 720S Spider (and the fire-spitting 600LT Spider we showed you last week). Unsurprisingly, in just about every aspect, it's a better car than the one it replaces. It's easier to get into and out of than the 650S Spider, thanks to the new tub. The sills are lower, the door aperture is wider, the roof header bar is further forward, and the rear buttresses are further back toward the rear.

Once ensconced in the driver's seat, you immediately notice the improved interior. There's a larger 8-inch infotainment screen that's now angled toward the driver, and the styling is much more dramatic than the 650S, which tended to have large, flat expanses of carpet or leather that gave some cause to complain that it felt like a kit car. The steering wheel remains one of the best ones you can wrap your hands around—the width and shape of the rim at 3 and 9 is based on Lewis Hamilton's old F1 car steering wheel—and there's not a button or switch on it, unlike those you'd find in a Ferrari or Lamborghini.

There's an all-new digital dashboard, which you can rotate to show a much-reduced display—this happens automatically when you put the car in Track mode, although you can toggle the behavior with a button on the dash, too. And one of my chief complaints about the 650S has now been fixed. In the old car, if you were approaching a parking ramp or speed hump and wanted to raise the nose, that required several inputs with the control stalk (which lives below the windscreen wiper stalk on the right side of the wheel). That control stalk is still there, but if you want to raise the nose now, there's a little button right on its tip. However, I don't remember the footwell of the 650S being quite so cramped.

Jonathan Gitlin

Jonathan Gitlin

Jonathan Gitlin

On the move, the car can be as sedate as you want it to be. The aluminum throttle pedal has plenty of travel, so you won't accidentally rear-end someone if you sneeze, and in automatic mode the gearbox happily does its own thing. Forward visibility is very good, and rear visibility is acceptable for a mid-engined convertible, although I'm not sure McLaren's claims that the glazed rear buttresses help you look over your left shoulder are accurate—perhaps I'm just too short to find out. With the roof up at cruising speed on the highway it's all very refined, and it's not that bad top-down at 70mph (112km/h).

Things get more interesting when you take more control over the driving experience. Again, as with all McLarens, there are separate mode controls for the handling and the powertrain, each offering settings of Comfort, Sport, and Track. For the handling modes, comfort makes great use of the car's fancy interconnected front-rear suspension (for a lengthy description of how this works, please refer to the 650S Spider review) giving the 720S a ride that some executive sedans would envy. From there, things get progressively stiffer and more performance-oriented, although even in Track mode, the ride was never particularly harsh.

Escalating the powertrain from Comfort through Sport and then to Track remaps the throttle response. Additionally, in Sport it will cut ignition to the engine momentarily during gearshifts, and in Track the flywheel delivers an extra impulse of torque on each upshift (McLaren calls this Inertia Push) for more seamless gear changes. That might sound like marketing guff, but the seven-speed 'box feels remarkable in Track, with no perceptible hesitation when you grab the next ratio under hard acceleration.

As we only drove the 720S on the road, we didn't get close to its handling limits, but those are apparently more exploitable now, thanks to a new generation of Proactive Chassis Control software. In supercars like these, there's always the danger that driving at legal speeds feels boring because it's so far below the car's limit. While the 720S did feel a little less alive than Ferrari's 488 cruising at 70mph, the feedback through the steering wheel was communicative and always engaging. Other than the cramped footwell, my only complaint was the soundtrack, or lack thereof. A turbocharged engine is always going to sound boring and muted compared to a naturally aspirated one—just compare the Ferrari 488 with its predecessor if you don't believe me—but it is possible to add some character, as the hardcore 600LT Spider proved a day later.

If the 650S Spider was a supercar with a PhD, that must make the 720S Spider a supercar that just landed a tenured position straight out of grad school.