The Park Avenue Ultra is Buick's flagship, a supercharged luxury sedan targeted at offerings from Lincoln, Cadillac and the imports. It offers gobs of space, plush seats and vigorous performance.

The front-wheel-drive Park Avenue line was completely new in 1998, so changes for 1999 consist of minor revisions to the tail lamps and the addition of four new colors. Pricing ranges from $31,800 for the Park Avenue to $36,695 for the Park Avenue Ultra.

The key difference between the two can be found under the hood. Both use General Motors' 3.8-liter, 3800 Series II V6, but the one in the Ultra is supercharged and puts out 240 horsepower. The non-supercharged model has 205 horsepower.

Our Park Avenue Ultra, from Buick's press fleet, had a hefty sticker price of more than $37,000.

The supercharged engine pounds out power like a small V8, it produces traces of coarseness that send a tingle through the steering wheel as you step into the throttle from idle. Things smooth out quickly as speed increases. The non-supercharged engine is smoother, not to mention less thirsty, and its performance is more than adequate in most driving conditions.

Visually, distinguishing the Ultra from the regular Park Avenue is also tough. The clean, yet conservative styling not only perpetuates the Park Avenue persona but also fits in nicely with the rest of the Buick family.

A long list of standard equipment really sets the Ultra apart. Leather, heated seats with memory settings, wood trim, steering wheel controls for radio and temperature and full-range traction control are among the key distinctions. The Ultra also has a standard CD player.

Buick chose to base this generation Park Avenue on a platform derived from that of the Oldsmobile Aurora. It has 113.8-inch wheelbase and structural integrity and stiffness that resists flexing and reduces the number of squeaks and rattles.

A stiff chassis gives engineers a chance to tune the suspension for a compliant ride without sacrificing responsiveness. The Ultra rides with a firmness that reflects the ability to take turns and lane changes without wallowing.

Paradoxically, I found the suspension felt less confident on highways with undulating pavement. A Gran Touring suspension package is available. Seats have long been a Park Avenue trademark, and those in the Ultra were no exception. The padding was firm, for excellent support, yet the seats were contoured to fit a wide variety of body types.

White-on-black gauges dot the instrument panel, which was accented with a highly polished strip of wood. Auxiliary controls for radio and temperature control are built into the steering wheel. When the gear lever was in Drive, it obscured the switch for the drivers seat heater.

The Ultra also has a standard Driver Information Center that calculates fuel economy, useful oil life, coolant level and tire pressure.

The test car was equipped with Eye Cu e, a head-up display that projects a small digital speed readout on the windshield so it appears to be floating out at the end of the hood.

A notable option is a big center console whose top flips forward to reveal two large cupholders and a place for a cellular phone. The lid to the middle storage compartment has a writing surface and place for a notpad on its underside. Called the Convenience Console, this $185 option is especially appealing to folks who use their cars as mobile offices. One drawback, however minor, is that it prohibits three people from riding in the front seat.

As you would expect of a car with a 206.8-inch overall length, the trunk capacity is 19.1 cubic feet.

Price: The base price of our test car was $36,695, including freight. Optional equipment consisted of the Eye Cue head-up display and the Convenience Console. The sticker price was $37,255.

Warranty: Three years or 36,000 miles.

Point: Great sea , room for five and a big trunk are among the strengths of the Park Avenue Ultra. A supercharged V6 gives it V8 performance.

Counterpoint: The supercharger accounts for tingles of low-speed vibration and the suspension seemed surprisingly soft over highway undulations.

ENGINE: 3.8-liter, V6
CONFIGURATION: Front-engine, front-wheel-drive
WHEELBASE: 113.8 inches
CURB WEIGHT: 3,884 lbs.
BASE PRICE: $36,695
MPG RATING: 18 city, 27 hwy.