Plainly, the 2013 McLaren MP4-12C Spider is a fantastic idea. It goes like this: Start with the 616-horsepower MP4-12C coupe, replace its fixed roof with a retractable hardtop that folds away in 17 seconds and limit the inevitable weight gain to 88 pounds. Oh, and have the hardtop's storage compartment double as a miniature second trunk for two custom duffel bags when the top's up. With a résumé like that, the Spider's roughly 10 percent price premium seems almost reasonable.

Of course, 10 percent in this case comes out to more than $25,000, so the Spider had better be fantastic. And for some supercar fans, the McLaren may not be sufficiently soul-stirring to justify the price. Let's be clear: The 12C Spider is one of the fastest and most capable cars ever built, so the problem isn't talent. Rather, the Spider is so good at what it does that it can make speed seem too easy -- as opposed to, say, the classic temperamental supercar that wants to rip your head off.

But if we're talking about supercars for the modern age, the MP4-12C Spider is perhaps the best one yet. It's not just about the dizzying speed (top speed drops by 3 mph, by the way, from the coupe's 207 to 204 here); there's also the user-friendly handling, the telepathic dual-clutch transmission and the finely crafted interior. Thanks to the brilliant adjustable suspension, you could even comfortably commute on city streets in this thing.

We'd be remiss not to mention compelling rivals like the Ferrari 458 Spider, the Lamborghini Gallardo convertible and the Mercedes-Benz SLS AMG convertible, but arguably none can match the McLaren's comprehensive mastery. If you want your convertible supercar to be as much of a perfectionist as you are, the 2013 MP4-12C Spider is a fantastic choice.

The two-passenger, midengine, rear-wheel-drive 2013 McLaren MP4-12C Spider is a retractable-hardtop convertible offered in one well-equipped trim level. Standard features include 19-inch front wheels and 20-inch rear wheels, bi-xenon headlights, power-folding and heated outside mirrors, LED driving lights, an active air brake, an adaptive suspension with three driving modes, an "intake sound generator" with selectable engine-sound levels, cruise control, manually adjustable seats (power height adjustment for the driver), leather and faux-suede upholstery and trim, a 7-inch touchscreen display and a four-speaker Meridian audio system with Bluetooth streaming audio, a USB port and iPod integration.

Options are plentiful and pricey -- even the paint costs extra in most cases. Highlights include an adjustable-height suspension for easier driveway ingress/egress, contrasting-color or carbon-fiber body elements, parking sensors, three styles of lightweight wheels, carbon-ceramic brakes, painted brake calipers, a sport exhaust, a full leather interior, a semi-aniline leather interior, carbon-fiber interior trim, six-way power heated seats with lumbar adjustment and memory functions, a fire extinguisher and a navigation system with seven-speaker Meridian surround-sound audio. The Stealth Pack adds a satin black finish to the exhaust tips and rear wing supports.

The MP4-12C Spider also offers fully customized interior treatments through McLaren Special Operations, including bespoke fabric and colors.

The 2013 McLaren MP4-12C Spider features a twin-turbocharged 3.8-liter V8 that pumps 616 hp and 443 pound-feet of torque to the rear wheels. The transmission is a dual-clutch seven-speed automated manual with paddle shifters.

In Edmunds performance testing, the slightly less powerful 2012 MP4-12C coupe accelerated from zero to 60 mph in a fleet 3.2 seconds.

The MP4-12C Spider's fuel economy had not been rated by the EPA as of this writing, but we expect it to fall in line with the coupe's 18 mpg combined (15 city/22 highway).

Standard safety equipment for the 2013 McLaren MP4-12C Spider includes antilock disc brakes, six airbags, hill-start assist, and traction and stability control. Carbon-ceramic brake rotors are available as an option. The Spider also features strengthened steel structures behind the passenger compartment for rollover protection.

The 2013 McLaren MP4-12C Spider's default engine note is relatively sedate (drive the rowdy Mercedes SLS drop top for a little perspective), but McLaren does provide a separate intake sound control for 2013, allowing you to tailor the engine's volume to the occasion. Also, every V8 sounds better with the top down, so the Spider is easily the more sonorous of the MP4-12C twins.

If there's one fly in the Spider's ointment, it's the top-down wind buffeting at highway speeds, which is surprising given that the MP4-12C was designed from the get-go with a convertible in mind. But in all other respects, this McLaren is one of the most gratifying and versatile driver's cars the world has ever seen, from its incredibly precise steering and racecar-like handling to its compliant suspension and savvy electronic driving aids. The Spider won't scare you -- it's too civilized for that -- but you'll still find yourself walking away in awe every time you take a spin.

Race-inspired touches abound in the MP4-12C Spider's cabin, including a large center-mounted tachometer and a flat-bottom steering wheel. Thankfully, though, the overall effect is understated and classy, with attention to detail that rivals the best luxury cars: Practically every surface you touch and switch you press feels rich. The standard faux-suede dash resists windscreen glare, while the enveloping sport seats provide firm support for all types of driving.

Most of the MP4-12C Spider's controls are housed in an unusually narrow center stack that sweeps gracefully between the seats. McLaren has artfully integrated everything into a simple, elegant presentation, with the touchscreen display oriented vertically to maximize available space. The dual-zone climate controls are smartly relocated to the doors, which helps give the center stack its uncluttered appearance.

As for the Spider's two-piece retractable hardtop, it offers a novel glass rear window that can operate independently, serving as a slide-up wind deflector with the top down and potential extra ventilation with the top up. The two custom McLaren duffel bags that fit under the tonneau cover are another nice touch, giving the Spider slightly more cargo capacity than the coupe (both share a 5.1-cubic-foot front trunk).