You have to wonder if you're getting effete when you send back an $80,000 car - kind of like refusing a $400 bottle of wine . . .Well, okay, they repossessed it - but I wasn't all that unhappy to see it go.The flagship Jaguar, despite its many enticements, is neither as much fun to drive or as posh (to borrow a Briticism) as the comparable offerings from Asia and Germany. It has, frankly, fallen behind.I was privileged to drive one of the 240 XJR 100s the British subsidiary of Ford Motor Co. will send to the colonies this year. Of all the XJ series - the big sedans - this one stands at the pinnacle.The XJR series per se features a supercharged V-8 engine for those who like to dream about touring at twice the national speed limit, and getting to that speed in a hurry.The "100" part is a tribute to the 100th birthday of Sir William Lyons, who founded Jaguar. Not just a cosmetic enhancement, the 100 package ($6,950) brings to the party 19-inch BBS modular wheels, the largest available in this line, Brembo brakes with cross-drilled rotors and a number of specific trim items, including what they call a red-stitched black leather interior. (To me, it looked orangeish, and rather out of place; but I AM a commoner.)No question - the big Jag is the most distinctive, and most appealing-looking of the mega-cars, by which I mean Audi A8, BMW 7 Series, Mercedes-Benz S class, Infiniti Q45 and Lexus LS430.Even without the chromed "leaper" (a pouncing Jaguar) hood ornament, it would be instantly recognizable in that big-bucks crowd. It looks as if it's about three feet tall. Actually, it's 52.7 inches high, which is only about 4 inches less than the competition, but it's enough to make it look striking.It's also enough to make it very unpleasant to get into if you're anywhere near the 6-foot range. The roofline is of course low, the seat is fairly high and the blasted steering wheel has only a slight range of tilt; there's no way to ease into this car swiftly or without forethought. That may be fine for a two-seater - heck, I could get into jumping over the door in one of those - but not in a luxury ride. Fitting a decent American tilt steering wheel would help the driver a lot.The driver, in turn, would have to give up some of his legroom to accommodate even average-sized adults in the rear. There's a long-wheelbase XJ which I'd consider if hauling another couple were a priority.Once you've wrapped the car around you, you can luxuriate in the visual, tactile and olfactory sensations which the British are so adept at providing. Connolly hides, of course, just like Rolls-Royce, buttery soft and redolent. Burl walnut trim that seems too good to be true, but you just know it is. (A matter of taste, but I'd prefer the dark honey stain to the "sporty" charcoal treatment they've given the XJR wood.)Fit and finish in line with the rep of limited-edition British cars.The XJR weighs a trifle over two tons, not so bad for this class. If it had the standard engine's 290 hp, it would be a brisk performer. With the 370 ponies a supercharger flogs out of the 32-valve V-8, it's practically a hotrod. (The thirsty V-12, alas, has been retired.)Torque is more of an issue, of course, especially in speed-constrained societies, and with a maximum of 387 foot-pounds (achieved at 3,600 rpm), the XJR is well-qualified there, too. The big Jag does not have the explosive launch feel one would get from a big pushrod American V-8 with comparable numbers. It takes off in a dignified fashion. The rear tires (huge 255/35s with the 100 package) showed no sign of losing their grip even when I dumped the throttle.The supercharger helped produce a smooth flow of power on up to about 3,500 rpm, and then things started to happen very quickly indeed. The surge was akin to what one experienced with old-style turbochargers - like going on afterburner. Net result was 0-60 times in the sub-6-second range, which would leave most sporty little cars in the dust. Good thing, too, because we'll never exploit (legally) this car's ability to cruise at mega-velocities. The speedometer went to 170 mph, which I'd guesstimate (honest, officer), was not exceedingly optimistic.The Jag does demand some attention to the speedometer; thoroughbred that it is, it hunkers best when the speedo gets into the three-digit range (so I read in a book), and auditory clues are insufficient to let you know you're being indiscreet.Speed - even when you don't get caught - has a price. A blueblood like this of course was raised on premium fuel, and it has become quite fond of it. The EPA estimates are 16 mpg city, 22 highway. That level of conspicuous consumption brings with it a $1,300 "gas guzzler" levy, which given the audience at this price level, is a bit silly. My 15.7-mpg tally suggests either I was listening to Satan too often or my math skills need polishing.With those monster contact patches, the Jag feels obsessed with keeping in touch with the pavement, and the chassis is sufficiently rigid - if not quite up to today's standards - to make it feel as tossable as a sporty compact.Like its fellow luxury rides, the Jag comes equipped with both the more mundane traction control and "stability control" - an interplay of sensors and computers designed to keep the driver out of trouble by not allowing him to ask for more turning angle than, at any given moment, the car is capable of delivering.The Jaguar's was particularly sensitive, I thought, not even allowing the rear end to swing out on wet surfaces. It intervened with braking force and a power cut almost before my driving coach could articulate concern - and that's fast. What fun is that? Happily, those who enjoy the sense of being master of the mount (and are a little crazy) can disable the censor.Handling was a bit rubbery and vague at times, although the car remained tenaciously wedded to pavement wet and dry. Ride quality was, for this class, a bit harsh, despite the Computer Active Technology Suspension (CATS - get it?), which purportedly adjusts the shock absorbers in response to driving conditions. Pity there's no "plush" setting - an $80-grand ride should exclude life's unpleasantries, as do the competitors.As I checked tire pressures, I noted a curious bit of advice in the owner's manual. Stipulated pressures "for comfort up to 100 mph" are 26 front, 28 rear. "Normal" pressures are defined as 32/34. That's quite a margin, and suggests Coventry is sensitive to owner's commentaries on the ride harshness. I made them 32/34.The XJR's brakes were simply awesome; however, upon delivery, they showed a tendency to pull to the left. Some extremely-high-rate stops seemed to even them out a bit, and stopping distances were extraordinarily short, without a hint of fade. Antilock, o f course, and of course it purred. Sorry.The navigation system is, compared with others available much farther down the food chain, pitiful - small, poorly placed, and hard to read.The power sunroof, I submit, would be more appealing as a moonroof, i.e., with glass instead of steel, so as to lighten the interior.The XJR's upgraded Alpine sound system was excellent in both sensitivity and tonality.Neither the Feds nor the insurance folks have seen fit to crash this low-volume piece. It has front and side air bags, but lacks head-curtain air bags, which are an emergent "must" in this range. With its maneuverability and mass, I'd nonetheless consider the big Jag a fairly survivable platform.Base price on the XJR is $71,830. Add in the X100 package, guzzler levy and freight, and you get a tidy $80,725.If one needed to subject oneself to the indignity of time-financing, the monthly levies would be $1,637. This assumes 20 percent down, 10 percent interest and 48 payments.