Jaguar's large flagship four-door sedan, the elegant 2007 XJ, is also its most technologically advanced. A lightweight monocoque structure made up of bonded and riveted aluminum elements underpins an exterior design that appears almost unchanged from the previous six generations of XJs.

Still, buyers don't choose a Jag because of the technology involved. The XJ has all the sensuous wood, leather and chrome expected of this storied British marque, combined with sophisticated road manners, surprisingly nimble handling and excellent performance from the 4.2-liter DOHC 32-valve Jaguar V8 -- in either naturally aspirated or supercharged form. Beyond that, this seventh-generation XJ (introduced as a 2004 model) is the roomiest XJ yet in both short- and long-wheelbase models.

However it's still a rather idiosyncratic machine. The ventilation controls would baffle a cryptologist, the "J-Gate" shifter topping the six-speed automatic transmission operates with scattershot imprecision and other controls seem to be designed with frustration in mind. Happily, the XJ isn't hobbled by sharing components with lesser machinery from parent Ford's catalog, but if what you want is a thoroughly rational car, buy German or Japanese. This car is, quite defiantly, not an Audi, BMW, Infiniti, Lexus or Mercedes.

Interestingly, the most controversial element of the 2007 Jaguar XJ is how conservatively it's styled. The XJ styling idiom -- four more-or-less circular headlamps bracketing a rectangular grille up front, an arched roof line and drop-away tail -- was set way back with the first XJ6 in 1969 and since then it was assumed that that styling was "timeless." Apparently, though, that assumption was wrong and many are clamoring for a more contemporary styling to reflect the XJ's leading-edge construction. That fresh styling is likely to come with the next XJ.

So if this how you think a Jag sedan should look, get your XJ soon.

The 2007 Jaguar XJ series comes as five separate models: base XJ8, XJ8 L with an extended wheelbase, supercharged and performance-oriented XJR, hyper-luxurious Vanden Plas and ludicrously luxurious and supercharged Super V8. The XJ and XJ8 L come with 18-inch wheels, a Computer Active Technology (CATS) active damping suspension, xenon headlamps, rear park control, Bluetooth wireless ability, a moonroof, power-adjustable pedals, power everything else and, of course, plenty of burl walnut trim.

For the Vanden Plas, Jaguar adds front park control, a heated wood-and-leather steering wheel, a navigation system, lambswool foot-well rugs, fold-down picnic trays for the rear seat passengers, an electric rear sunblind, power-folding exterior mirrors and a premium audio system. The high-performance XJR is based on the short-wheelbase body and gets 19-inch wheels, high-performance tires, an "R Performance" brake system, front park control, radar-adaptive cruise control, a sport-tuned suspension and expected luxuries like the navigation system, more powerful stereo and power-folding side mirrors.

Finally, at the tippy top of the Jaguar line, is the Super V8 that marries the XJR's blown engine with the long-wheelbase body and wears 19-inch wheels. Of course it gets the "R Performance" brakes and the front park control radar-adaptive cruise control, and everything else an XJR has. But it also has the Vanden Plas' fold-down picnic tables, a rear DVD multimedia entertainment system with twin display screens, and a four-zone climate control system.

That four-zone climate control system is an option on the Vanden Plas and XJR and so is the DVD multimedia entertainment system. Twenty-inch wheels are available for the XJR and Super V8, and much of what is standard on the Vanden Plas is optional on the XJ8 and XJ8 L. If that's all not enough, Sirius satellite radio is an option across the board.

All 2007 Jaguar XJ-Series sedans are rear-wheel drive and powered by Jaguar's 4.2-liter V8. The XJ8, XJ8 L and Vanden Plas use a naturally aspirated version rated at 300 horsepower while the XJR and Super V8 add a Roots-style supercharger to swell total output to 400 hp. A six-speed automatic transmission is standard on all XJ models. Edmunds.com's test of the mechanically identical 2005 Super V8 had it accelerating from zero to 60 mph in just 5.6 seconds.

Jaguar's "Adaptive Restraint Technology System" monitors the positions of both the driver and front passenger instead of merely their weight when deciding how and when to deploy the front, side and side curtain airbags. Antilock brakes and stability control are also standard.

Operating in virtual silence, with a suspension system tuned more for grace and dignity than corner-carving, the 2007 Jaguar XJ-Series sedans have a personality unique among high-end luxury cars. But with their lightweight construction and the surprisingly eager V8 aboard, they're also surprisingly rambunctious when given some spur. If you want a Jaguar, there really aren't any substitutes.

Every 2007 XJ-series sedan interior is finished in wood veneers, luscious leather and absolutely tasteful chrome accents. Where other luxury cars try to impress with overwhelming technology, the XJ has the feeling of a British manor's study — it lacks only bookshelves and brandy snifters. Still the XJ's interiors could be better; many drivers find the seats unaccommodating, some of the switchgear has a tactile cheapness to its operation and there's nothing intuitive about their operation.