The story here is a simple one, with McLaren engineers deploying a power-retractable hard top in place of the MP4-12C’s fixed roof, and leaving well enough alone with the rest of the car. The hardware for the top adds just 88 lbs. to the Spider’s curb weight—3,033 lbs. in standard trim/2,956 lbs. in its lightest configuration—and can let the sun shine in in less than 17 seconds, at speeds up to 19 mph. The opening itself isn’t huge, but that’s probably for the best at triple-digit speeds, and it allows the car to look very natural regardless of whether the top is open or closed.

Particularly helpful in this regard is the design of the Spider’s rollover protection system, disguised beneath buttresses that flow back behind the driver and passenger seat in a way that maintains much of the silhouette of the Coupe. Also maintained: McLaren’s hallmark “dihedral” doors. Yes, they’re suitably exotic, but they also showcase the company’s commitment to driver practicality. Thus, they open up and forward in dramatic fashion, but they also take part of the car’s lower sill with them for further ease of entrance/exit, and can be opened with less than two feet of side clearance.

There’s also another bonus to the car, according to Antony Sheriff, managing director for McLaren Automotive: “While the 12C is the technological essence of a race car, the 12C Spider incorporates an additional dimension. 12C Spider owners will love the opportunity to lower the roof and hear the unhindered howl of a V8 twin-turbo engine at full throttle. It undoubtedly enhances an already euphoric 12C driving experience.”

The rest of the 2013 McLaren MP4-12C Spider hews quite closely to the template of the Coupe, but that’s not a bad thing. Mounted just behind the driver is one of McLaren’s 3.8-liter twin-turbo V8 engines, capable of making 616 hp and 443 lb.-ft. of torque, and mated to a seven-speed SSG dual-clutch transmission. But the real difference-maker here is McLaren’s Lotus-like dedication to low curb weights. As mentioned, the Spider adds just 88 lbs. to the bottom line of the Coupe, which, in turn, is one of the lightest cars in its segment, thanks to its carbon-fiber construction.

McLaren helped bring that material into the mainstream in earlier cars, and the company’s expertise allowed it to devise a unique “monocell” body structure that is literally a single piece of molded carbon fiber. It weighs just 165 lbs., yet is so strong that no additional bracing was needed to open up the roof of the Spider.

As a result of those weight-saving efforts, the MP4-12C Spider also is expected to return the same EPA line of 15 mpg city/22 mpg highway/18 mpg combined as posted by the Coupe; the numbers may look ugly at first glance, but the 458 only posts an EPA line of 12/18/14, and that’s with a stop/start system.

More important for most buyers is the fact that the 2013 MP4-12C Spider’s incredible power-to-weight ratio enables it to run from 0-62 mph in 3.1 seconds, and from 0-100 mph in 6.1 seconds, and keep running all the way up to its 204 mph top speed; the quarter mile is achieved in 10.8 seconds @134 mph.

The 2013 McLaren MP4-12C is available for ordering now, in 17 exotic exterior colors, and is slated to reach customers early next year with standard and available lux touches that include:

• Bluetooth technology
• Heated seats
• A seven-inch touchscreen controller for key vehicle functions
• Premium surround-sound audio from Meridian
• Satellite-based navigation
• A variety of attention-grabbing wheel designs
• Front and rear parking sensors
• A full leather interior
• Carbon-fiber interior and exterior accents
• LED lighting
• Rain-sensing windshield wipers
• Power, heated exterior mirrors
• A three-mode driving system with Normal, Sport and Track configurations