Somewhere east of Cape Town, South Africa, on a sinuously twisty road that hugs tall, ocean-side cliffs like a python encircling its prey, my temptation to pass a line of dawdling tourists is overwhelming. But as we pull out to pass, the passing lane abruptly ends. The serpentine road curves sharply around a bluff, momentarily blocking our view. Suddenly, an oncoming motorist appears, a few hundred yards ahead, squarely in our path. In the space of an instant, the only decision is to snap-shift down, nail the gas, crank the wheel to the left and thread a rapidly contracting needle's eye.

The new XK responds like a thoroughbred to the spur. In split seconds, we shoot around the line of dawdlers, juke back in our lane, ahead of the oncoming car and safely out of harm's way. Had we been driving something else, I might not be writing this. But for the newest Jag, that deft maneuver was, as the Brits say, a "piece of cake."

Sir William would be proud
The fabulous Jaguar E-Type was a sensation in its day — a glamorous 1960s stiletto heel of a car — slim, elegant, powerful, capable of nearly 150 mph — and able to take on a Ferrari at half the price.

After the E-Type came a long series of somewhat compromised cars. While recognizable as Jaguars, they were grand tourers, not true sports cars. Coventry's cats aren't supposed to be hard-edged racers, but they've got to be capable mile-eaters that can accelerate hard and sweep through a succession of tight, decreasing-radius turns without breaking a sweat. The company's founder, Sir William Lyons, summed it up as "grace, space and pace."

But competition today is ruthless. The newest coupe and convertible have to be the best Jags in four decades.

And they are.

Tuned reflexes
Jaguar's huge investment a few years back in an aluminum stamping plant is paying off. The 2007 XK's bonded and riveted monocoque alloy substructure is 34 Hz (a Mercedes-Benz SL is 26; a BMW 6 Series is 30), some 50-percent stiffer than its predecessor and more than 400 pounds lighter. That's aircraft technology. Here's what it means:

When a car's chassis and body are really rigid, engineers can fine-tune the suspension to a fare-thee-well. Jaguar's improved Computer Active Technology Suspension (they call it CATS, naturally) is a highly sophisticated, two-stage adaptive damping system with sensors that measure the XK's attitude, pitch and yaw, steering wheel angle and brake demand, then adjust all four shocks independently in nanoseconds. There's two-stage Dynamic Stability Control (DSC) as well, so the new XK corners like a racecar, with no drama.

The proper feline for a cat-quick beeline
This car's incredible lightness of being means it needs less power and uses less fuel. And it's ULEV II rated. OK, you can get 300 horsepower in a Subaru WRX these days, but in the 3,671-pound coupe (the convertible is just 88 pounds more), the high-revving, 4.2-liter four-cam V8 with Variable Camshaft Phasing (VCP) feels like a lot more motor. (We can only imagine what the 400-plus-hp R-Type will be like.)

In the meantime, the newest XK iteration is bloody fast, with variable valve timing, 310 pound-feet of torque, perfectly weighted steering, and new race-inspired ventilated disc brakes with ABS and EBD.

There's a brilliant six-speed sequential-shift ZF automatic, with hyperquick paddle shifters (try 400 milliseconds between shifts), and three distinct driving modes: "Drive Automatic," "Adaptive Sport Automatic" and "Sequential Manual" for immediate response that's better than any gear twirling you could ever do with a standard stick. It stacks downshifts under braking, blips the throttle before it drops a gear and shifts very close to the 6,000-rpm redline.

High tech, low weight and mean muscle
Jaguar's included all the mod cons — likweight and mean muscle
Jaguar'e keyless entry and starting, two-stage unlocking, Adaptive Cruise Control, active front lighting, an LED backup light, ultrasonic rear parking aids, Forward Alert (which uses the front parking sensors to warn of an impending collision), and much more.

The rigid body's low mass helps reduce energy on impact. In the unlikely instance they're ever needed, the fast-acting, pop-up aluminum roll hoops actually pierce the convertible's glass rear window (in 60 milliseconds) when they're activated. But do you really think Jaguar would have that happen if it actually thought this cool customer would ever lose its composure?

Styling is subjective, but we think Jaguar's design chief, Ian Callum, (who penned the Aston Martin DB7 and the Vantage V12), has drawn a modern Jaguar 2+2 that's worthy of the marque's heritage. Outside, the new model's curvaceous exterior evokes that of the revered E-Type, but the '07 is clearly contemporary, mature and undeniably sexy. "There's no fat in this car," Callum says proudly. "It's an athlete."

A functional vertical side vent in each front fender is topped by a discreet Jaguar badge that helps break up the panel's expanse. "We wanted people to look sideways at a stoplight and know immediately what it is," says Callum. As if that weren't obvious with the XK's long, sweeping hood; selfish cabin; muscular rear shoulders; and handsome 18-inch, flared spoke alloy wheels that anchor the corners and completely fill the radiused wheelwells.

The In Crowd approves
Inside, deep, well-bolstered bucket seats grip you securely, and they feel great on long drives. Traditional Jaguar fans can choose honey-toned burl walnut or lighter poplar wood accents; newer customers may opt for brushed aluminum. Either way, the interior is stunning.

The wheelbase is 6.4 inches longer and the XK's about 3 inches wider than its predecessor, so the cockpit is generously sized without losing that sports roadster coziness. An electronic parking brake eliminates the old protruding fly-off lever. Those vestigial rear seats were retained after clients told researchers they didn't want a folding metal roof (because it would have made the car's butt too wide), and they really wanted small, practical rear seating that's fine for smallish people over short distances.

With the push of a button, the XK's triple-layer convertible soft top folds using hydraulic actuators and electronic controls in just 18 seconds. The side windows and rear-quarter glass are raised at the end of the cycle. It's stored beneath a trim tonneau cover. Fully folded, there's still room for 2+2 seating.

When the top is up, if you stow the retractable load-space separator, there's an additional 3 cubic feet of storage space. Designer Ian Callum said that his team looked at a folding hardtop, but they did not want to pay the weight penalty, and they would have had to make the XK wider in the rear, compromising its slim profile.

The Cat is definitely back
On South Africa's smooth, sweeping roads, we reveled in the throaty roar from the two-stage muffler. At idle, it purrs; under hard acceleration, there's a yowl reminiscent of the thrilling note from the parallel exhaust pipes of Jag's classic XK120. Time after time, we ran the XK through its gears just to hear their symphony. And on the twisty Killarney racetrack, we switched off the traction control and marveled at just how controllable this new XK is — a flick of the wrists gathered it up every time.

Oh, and here are the numbers according to Jag: zero to 60 mph is 5.9 seconds. The quarter-mile takes just 14.4 seconds. Add a tenth to both for the convertible. Top whack is electronically limited to 155 mph. The massive brakes are incredible, powerful enough to stop the car in just over 113 feet from 60 mph. Fuel mileage is 18 mpg city, 26 mpg highway.

The 2007 Jaguar XK coupe and convertible go on sale in April, priced at $75,500 for the coupe and $81,500 for the convertible. They'll go quickly.

Preparing for a proper drive in the 2007 Jaguar XK Convertible brings on a mix of emotions. In many ways this is a brilliant topless GT that makes us want to indulge in its opulence. It's magnificently easy on the eyes, makes all the right sounds and is quick enough to not embarrass itself. Hell, the car didn't even leak one drop of fluid — on the ground or the driver. Better still, the urge to toss our stringback gloves into the wind was undeniable.

You see, this isn't the British roadster we had in our heads. Gone are the days of the creaking chassis, tractor engine and Lucas electronics. The 2007 XK Convertible is a thoroughly modern machine that delivers the experience directly in line with its lofty price tag and the desires of its target audience.

The question, then, is, are you in that audience? Here's a quick do-it-yourself test to find out. Before retirement, was your title followed by the letters MD, JD or CEO? Do you think golf is not a four-letter word? Is there a pair of stringback gloves mothballed in your closet? If the answer is yes to any of these questions, there may be an XK convertible in your future.

Going topless
The XK convertible shares its underpinnings with the 2007 Jaguar XK Coupe, which we compared to the BMW 650i Coupe earlier this year. That is to say that it shares the coupe's basic structure, 4.2-liter 300-horsepower V8 and 6-speed paddle-shifted automatic transmission. In fact, the only real difference is the retractable soft top, which disappears underneath a hard tonneau cover in only 18 seconds with the push of a button.

That soft top is a magnificent piece of work that insulates its occupants from noise and the elements with the luxury we'd expect from a car this price. It takes three layers to get the job done. The outer layer is waterproof cloth, the central layer is 3M Thinsulate and the inner layer is cloth lining. The heated glass rear window is bonded into the roof.

Retracting the top eliminates 3 cubic feet of cargo space from the already small trunk. Jaguar uses a retractable separator to block off the space occupied by the top when in the down position — a relatively elegant solution to a problem that's as old as the convertible itself.

Modern underpinnings, modern driving
Jaguar boasts that the new XK convertible is 50 percent stiffer than the car it replaces — and we believe it. The car's aluminum chassis is bonded and riveted together and is also lighter than the old XK platform. In fact, the aluminum doors are some 13 pounds lighter than their steel equivalents. Our scales told the tale less kindly with an as-tested weight of 3,891 pounds, so the XK convertible is no featherweight.

From behind the wheel the Jag does feel large, but it's not unpleasant. This is a big convertible in the grand tradition of big convertibles. Practicality and usability are tossed in favor of luxury and looks. The rear seat is a joke and the trunk is hilarious. But if cruising with the top down and listening to the song of the aluminum V8 is your thing, then the XK convertible is your car.

There's a big-car solidity to its ride quality. High-frequency bumps don't resonate in the windshield header and there's no sense of open-top flexiness. Don't plan any attacks on super-tight backcountry roads in the XK, though. It's not that kind of car. Yes, it handles well, but it's no Miata. Bend it into a sweeping corner and you'll be rewarded with consistent, intuitive feedback through the wheel, surprising grip and more agility than you thought possible from a car with this kind of mass. This is a big, easygoing cat, but a cat nonetheless.

Fast cat?
Speed, with the XK, is in the eye of the beholder. Our tests proved it's not overwhelmingly quick — 14.6 seconds at 96.9 mph through the quarter-mile including a 0-60 run in 6.3 seconds. But drop the top and mash the gas and you'd swear it will run a 13. It sounds fast. And in a car like this that matters as much as actually being fast.

The XK yanked itself around the skid pad at 0.84g and skipped through the slalom at a respectable 65.9 mph. It also stopped from 60 mph in 122 feet. Those aren't Porsche 911 numbers, but they don't really need to be.

It's no surprise that this isn't the quickest car around when one begins looking at the numbers. Three hundred horsepower and 310 pound-feet of torque isn't a lot of snap in a car that flirts with 2 tons. The 6-speed automatic transmission doesn't do all that much for acceleration either — it's a bit lazy off the line.

However, slap it over into Sport mode — accessed by sliding the shifter to the left from the drive position — and the big Jag's character changes considerably. In Sport mode the tranny hangs on to gears longer, allowing real engine braking when off the throttle. It also downshifts aggressively when slowing. This provides immediate response when transitioning back to the throttle rather than having to wait for a downshift — a critical and often overlooked factor in most automatic-transmission calibrations.

When using the steering-wheel-mounted paddle shifter, upshifts are quicker, too — 600 milliseconds according to Jaguar — and downshifts are met with a real throttle blip. Still, the tranny will upshift automatically should you run the engine to redline, rather than giving you a second on the limiter, which can be frustrating.

Devil in the details
We found several niggling problem areas on the XK that shouldn't exist on a car this expensive. The biggest issue surrounds the touch-sensitive screen that controls the navigation, audio, Bluetooth and climate control systems. It's simply not as sensitive as it should be. Successful navigation through its menus requires a jab rather than a touch to initiate a screen change.

Additionally, we found the screen out of calibration. Occasionally, touching the climate button would bring up the audio control screen. This is especially frustrating since the only way to completely shut down the climate control is through the touchscreen.

Bluetooth operation, however, is smart and intuitive. As a call rings in, radio volume is lowered and the system asks if you'd like to accept the call. Hit the "Accept" button and the music goes off all the way. The keypad is also conveniently large and doesn't go blank while the car is moving, but we had the same problems with the touchscreen calibration and sensitivity while using it as a cell phone interface.

Luckily, the rest of the interior is an exercise in detailed excellence. We especially like the electronically actuated parking brake, which is perfectly placed behind the shift lever. Soft-grain leather covers all the seating surfaces and leather also covers the instrument panel in cars equipped with the luxury package. That same package adds 16-way adjustable power seats with memory.

She'll run ya
Our test car landed with a $92,125 as-tested price thanks to the $8,125 Aluminum Luxury Package, which includes 20-inch wheels and tires, aluminum trim, soft-grain leather and 16-way power seats. It also came with the $2,500 Advanced Technology Package, which adds adaptive cruise control and active front lighting. XK convertibles start at $80,835.

A similarly equipped BMW 650i convertible will set you back slightly less at $85,695 and is arguably a better driving car. Still, there's a valuable element of exclusivity with the Jag and you'll be hard-pressed to find anyone who thinks the 6 Series is a better-looking car. What you choose might just come down to whether there's still a set of stringback gloves mothballed in one of your closets.