Jaguar's impressive heritage comes out in full force in XJR.

The X JR brings all of the best of Jaguar's rich heritage to play in a large sedan. The X JR combines svelte design and a take-no-prisoners supercharged V-8 engine to offer a fine combination of style and performance.

While we're particularly drawn to the X JR, there's a nagging question about the company's future. Jaguar saw its U.S. sales slip by 33.7 percent in 2005. For the first half of 2006, volume has fallen an additional 32 percent. This plunge is almost unprecedented for an established luxury car in the present era. Jaguar North America just announced the appointment of Marti Eulberg to the position of executive vice president of marketing and sales for Jaguar North America. With Jaguar's high market penetration among upscale female buyers, maybe a woman's touch can right the ship. On the other hand, Eulberg's experience has been selling Volvos. If you think of Volvo as a sensible shoe, like a Birkenstock, then the Jaguar market may be more related to high-fashion footwear, such as Jimmy Choo or Manolo Blahnik, where a list price of several grand is not unknown.

But back to the product. The first XJ was launched in the late 1960s and has been on an evolutionary trajectory since. The model has always been acclaimed as one of the most, if not the most, beautiful postwar sedans, but has had its ups and downs in terms of sales and reputation, mostly based on its reliability. Nevertheless, the SJ sedan is the heart of the Jaguar franchise and has commanded respect from auto lovers for its sleek lines and driving dynamics, even when its mechanical components weren't up to industry standards. But under Ford Motor Co.'s ownership, the bugs have been worked out and the big Jag can compete with the finest as evidenced by its high standing in the J.D. Power and Associates initial quality studies.

For the 2006 model year, the XJ range expands to six models to give luxury car buyers a broad range of price and alternatives. The short-wheelbase models are represented by the base X J8 with a base manufacturer's suggested retail price of $65,000 and supercharged, high-performance XJR, our test vehicle. The long wheelbase models include the XJ8 L, Vanden Plas, Super V8 and culminating with the new Super V8 Portfolio, with a sticker price of $116,000.

The sleek visual impact of the XJ's body is most apparent in its highly sculpted side view, the distinct grille and the four round headlights that are artfully sculpted into the hood as well as the subtle manner in which the car tapers at both ends into the front and rear fascias. Large, handsome 19-inch alloy wheels with high-performance tires cap the exterior design of the current X JR.

What's outstanding about the XJ sedan is its aluminum structure and the development of a construction technique based on the use of self-piercing rivets and advanced epoxy adhesives. The result is a car that's very stiff and light in weight. The benefit to the driver is a quieter, smoother ride and one completely free of chassis shake or shudder. The X JR is one of the most serene cars on the road, and yet can definitely hold its own on demanding mountain roads.

The Jaguar XJR is notable for its refinement and performance. With 400 horsepower on board, it offers effortless acceleration from zero to 60 mph in a scant five seconds and a top speed of 155 mph.

On supercharged XJ models such as the X JR, a new Conti-Teves R Performance system is incorporated, featuring ventilated 14-inch front rotors and 12.8-inch rears. The braking system is exceptionally smooth and responsive, among the best I've ever experienced.

The one area in which the current XJ series falls short is the design of the dashboard, center console and instrument cluster.

Although we can laud the fact that Jag does not attempt to overwhelm the driver with an excess of technology, as do the latest offerings from BMW and Mercedes-Benz, the whole assembly of gauges, controls and displays looks very dated and seems to follow no clearly defined organizational principle. A look at the current interiors from Audi and Lexus display elegance and design that now leave Jaguar somewhere in the last century.

Jaguar XJR

Price as tested: $84,995. Engine: Type: 4.2-liter supercharged V-8.

Horsepower: 400 @ 6,100 rpm.

Torque: 413 foot-pounds @ 3,500 rpm. Fuel economy, automatic transmission:

City: 17 mpg.

Highway: 24 mpg.

Curb weight: 3,958 pounds.

Cordell Koland is an automotive journalist based in California's central coast. He can be reached at [e-mail].