Most XJ models are tuned with emphasis on a supple ride, which is probably not a bad thing in a big luxury car. Yet all handle in steady, predictable fashion, and are quite nimble for cars of their size. Indeed, we'd say they offer some distinct advantages over their German counterparts.

One is the XJ's all-aluminum monocoque, or integrated body/chassis. It weighs about 400 less than a similarly sized unit-body fashioned of conventional steel, which is the equivalent of leaving two good-sized passengers at the curb. Rest assured that that the aluminum body is as crashworthy, as strong, as steel (stronger, actually, at a given weight). The Jaguar's body is built in essentially the same fashion as the airframe of a commercial airliner: riveted (with about 3200 rivets) and bonded (120 yards of adhesive) to form a stiff shell that is the foundation for everything the car does. Other things equal, this rigidity and reduced weight promote a better-riding, better-handling car.

Toss the big XJ into a tight corner on a narrow winding road and you'll find that it tenaciously grips the surface, with nary a complaint. The power steering is precise without being too heavy, and the XJ goes where it's aimed. The tires stay pressed to the road thanks to its double-wishbone suspension design and Jaguar's Computer Active Technology Suspension (CATS), which continuously and instantly adjusts damping according to forces pushing the wheels up toward the car. CATS promotes stability and a nice, even body height whether the car is accelerating or braking hard or traveling over an undulating road surface.

Through several hundred miles on a variety of different roads and surfaces, the XJ was stable at all times, with predictable handling. It didn't matter whether we were in the standard or long-wheelbase versions. The only intrusion in the smoothness was a bit more vibration through the steering column than we'd expect in a super luxury car.

The XJs are also quick, and again we see the value of aluminum. The XJ8's 300-horsepower V8 is down on power at least a bit to all its competitors, yet its acceleration figures (0 to 60 mph in about 6.3 seconds, according to Jaguar) are as good as or better than many, thanks to relatively light wieght. In the XJ, the V8 engine delivers plenty of acceleration-producing torque at all engines speeds, and it also delivers the best EPA mileage rating (at 18/27 mpg City/Highway, equal to the Lexus LS460) in the class.

The engine works nicely with the six-speed automatic transmission, which we still consider one of the best in the class, despite a proliferation of seven-speeds. Shifts are smooth, almost seamless, during sedate driving, yet positive under hard acceleration. Most importantly, the transmission is almost intuitive. In most cases, its electronic brain decides to change gears at almost the precise moment we would, if we were doing the shifting with a manual.

We're not fans of Jaguar's J-Gate manual shift selector, however. This device is a throw-back to the days before transmissions had advanced electronic controls, and engineers sought alternative means to give automatics a sportier, manual feel. We find the more familiar up/down sequential manual feature on most other automatics to be more effective than J-Gate. Regardless, the XJ's power band and the automatic's excellent response make manual shifting seem superfluous.

The XJR and Super V8 models add a supercharger that forces more air into the engine, raising both horsepower and torque by at least 100 units. This propels the XJR from 0 to 60 mph in 5 seconds, according to Jaguar, which moves into high-performance sports car territory and surpasses just about every V8-powered car in this class. Yet as much as the acceleration, it's the dynamic, full-throttle whir of the supercharger that sets the XJR and Super V8 apart from the rest of the pack. Enthusiast drivers really enjoy it, and the supercharged XJs suffer no gas-guzzler tax penalty.

The XJR is also the XJ tuned more for handling response than comfort. These rockets get a firmer suspension (with conventional steel coil as opposed to air springs), bigger brakes and fat 19-inch Z-rated tires (the highest speed rating available). It all serves to sharpen the XJR's steering response and allow it to grip the pavement more tenaciously. The ride, in our view, is not excessively harsh, even with the ultra-low profile tires.

Braking is what we expect in this class: powerful and generally smooth. The ABS system is effective in balancing brake force, even on rough roads, and the parking brake is elegant. It engages electronically, with a lever switch to set it, and releases automatically when drive or reverse is selected.