Please fasten your seat belts, put trays in the upright position and stow any carry-on luggage under the seat before pressing the accelerator on the 2000 Jaguar XKR, because the instant you do, you are going to experience launch.

No need to sit back. The XKR will do that for you by implanting your backside a couple inches deep into the cowhide as you hold the wheel with both hands and watch the scenery streak past.

For a brief moment you don't care if gas is $1.60 a gallon or $1.60 a pint and whether the air slapping the top of your melon has been sufficiently treated to keep the government happy.

Following on the success of its new small S-Type luxury sedan (Cartalk, May 23, 1999) that bowed last summer, Jaguar brought out the XKR coupe and convertible last fall, a high-performance model based on the XK8 sports coupe that's powered by a supercharged 370-horsepower version of the 4-liter V-8 offered in the XJR sedan and teamed with a 5-speed automatic. The XKR is in response to those wanting even more performance as well as excitement than the XK8.

The XKR boasts a zero- to 60-m.p.h. time of 5.2 seconds (5.3 with convertible), fastest Jaguar in the stable.

Stylewise, the XKR features a wire-mesh grille, functional hood louvers, decklid spoiler and 18-inch alloy wheels with Z-rated Pirelli performance tires--8 inches wide up front, 9 inches wide in the rear, developed for optimum steering response and high-speed stability.

We tested the 2000 XKR convertible, the open-top member of the XKR coupe and convertible duo of limited production high-performance Jaguars, the vehicle for those who want more kick than the XK8 coupe or convertible with its normally aspirated 4-liter, 290-h.p. V-8 can deliver.

The XKR comes with Computer Active Technology Suspension (CATS, the same as on the S-Type) that provides computer controlled suspension adjustments to maximize ride and handling, a most appreciated feature in between as well as during those power takeoffs. CATS is teamed with Servtronic II steering for sure-footed cornering, along with the typical Jaguar burl walnut and leather interior treatment.

Of course, once you've spent time playing rocket launcher, there are a few drawbacks with the car. For one, even with the CATS system, the suspension exhibited a slight case of the jitters on a stretch of lumpy, bumpy, pothole-pocked road. Of course, you might say, how would the XKR have performed on that lumpy, bumpy, pothole-pocked road without CATS? Have to admit the answer probably would have been not as well as it did.

On the much smoother interstate, CATS performed very well. If you hand over $81,800 for a XKR convertible ($76,800 for coupe), chances are you are going to spend more time on smooth surfaces than you will tracking down potholes, lumps or bumps.

Also, while those power launches were fun, each time we were slapped back into the bucket, the front end seem to rise for takeoff. What you want in a high-power bullet is for the front end to sit still--and level.

About the only other drawbacks with this toy were the fact that when getting out we noticed that the back of the driver's seat was against the cushion on the rear seat, meaning that anyone attempting travel in back woul d have to sit Indian style with legs folded on the seat, if political correctness allows such a description.

And, if you enjoy golf, be advised that the convertible hardware devours so much trunk room that you'll have to carry your clubs in the back seat, and even they'll have a tight fit.

Other standard equipment includes traction control with brake and engine regulation, a steering column that motors out of the way to allow for easier exit, a power top with heated glass window that can be closed even if you are traveling at speeds up to 10 m.p.h., heated seats, premium audio system with six-disc CD changer, power headlamp washers and rain-sensing windshield wipers.

All but the power headlamp washers are appreciated. The Lord gave us paper towels to wipe the lenses rather than using power headlamp washers. Besides, if you do enough power launches in the XKR, you will find yourself with the cleanest lenses in the county.

The only option on the XKR is a $2,400 navigation system, another item not really needed unless a sense of direction is beyond your realm, in which case you should be taking public transportation. The best navigation system in the world was designed years ago by Rand McNally, though in fairness, you don't have to fold the Jaguar unit.

One other XKR drawback--try to find one. Only about 5,000 will be sold in the U.S. for 2000 and all are accounted for. Jaguar says it will increase availability for 2001 but without exceeding demand. With high demand and low supply, be prepared to pay a ransom if you find one.

Jaguar insiders say one Wall Street banker type has been unable to acquire one though he has $5,000 deposits at five dealerships along the East Coast. Feel sorry for the poor soul, don't you?

Still to come from Jaguar is an even smaller luxury sedan about the size of a BMW 3-Series or Mercedes-Benz C-Class. It will arrive in calendar 2000 as a 2001 model. The car is now known as the X400 and will be the entry-level as well as high-volume sedan in the Jaguar lineup. It will not be shared with Lincoln, which has shelved plans to offer a version.

The X400 will be priced around $30,000, and Jaguar hopes to sell 40,000 to 50,000 annually in the U.S.

Also in the works is a high-performance two-seater. Last year Jaguar unveiled the XK180 concept roadster built off the XK8 coupe. It was powered by a 450-h.p. version of the supercharged 4-liter V-8. While two were built for show, none will see production, Jaguar says.

Instead, Jaguar has come up with the F-Type roadster design concept that is 25 inches shorter than the XK8. Jaguar has a team working on its development, and a decision to move ahead with production is expected in six to nine months. The two-seater could be produced within 30 months of approval and be on the streets within three years.

The F-Type still has to get the approval of Ford management as well as its boa rd. Chances of Ford President Jac Nasser giving the F-Type a thumbs down are slim and none.

"There's not a person in the company who doesn't want to build the F-Type," said Simone Sproule, director of public relations for Jaguar. "There's no shortage of passion within the company for it, and no shortage of buyer deposits that have been placed at dealerships in order to get one of the first ones."

The F-Type has no engine as yet. In fact, which engine, which platform and where to build it are the three hurdles to production. What is known, however, is that the F-Type would be the smallest car in the Jaguar lineup since the E-Type two-seater last sold in 1974, and that it would compete with the Porsche Boxster more so than the Mercedes SLK roadster, insiders say. Price: about $50,000. Production numbers: very low.

The X400 and F-Type, as well as the XK coupe, XJ and S-Type sedans, were made possible by Ford Motor Co.'s decision 10 years ago to acquire the automaker and provide Jaguar with not only the investment funds, but also the engineering and technology to bring out viable machines.

In calendar 1999, Jaguar sold 35,000 cars in the U.S., a 140 percent increase over 1998. Hard to believe, but 1999 was the first year the automaker advertised on network TV. Some will credit the ads for the sales increase; however, most will say a greater focus on quality and the introduction of the stylish S-Type that shares the platform with the Lincoln LS made a greater contribution.

The forecast for 2000 is sales of more than 40,000 units in the U.S. The goal, though no timetable has been set, is to sell 100,000 vehicles annually here once the lineup expands to five models: the XJ, S-Type and X400 sedans and XK and F-Type sports cars.

>> 2000 Jaguar XKR convertible Wheelbase: 101.9 inches Length: 187.4 inches Engine: 4-liter, 370-h.p., 32-valve supercharged V-8 Transmission: 5-speed automatic Fuel economy: 16 m.p.g. city/22 m.p.g. highway Base price: $81,800 Price as tested: $84,200. Includes $2,400 for navigation system. Add $595 for freight. Pluses: Solid top-down cruiser. Kick the pedal and hold onto the wheel because the supercharged V-8 will very quickly imbed your body into the cowhide wrapped seat. Power top can be closed even if you are traveling at speeds up to 10 m.p.h. Minuses: Front seat back touches rear-seat cushion, meaning rear-seat occupants must kneel on seat to fit. XKR will pass anything on road except a gas station. Golf clubs have to rest in back seat or you have to take up croquet because they ain't gonna fit in the trunk. Try to find an XKR, and if you do, better have the ransom money handy. >>