If the station wagon share of the U.S. new car market is small, then the space taken up in that segment by the luxury wagons is downright minuscule. At the present time, there are only a few players on this tiny field. Depending on your definition of the term luxury wagon, entries can be said to range from the Mercury Sable and Toyota Camry to the Volvo 960 and BMW 525i Touring, ending on the high side with the Mercedes 300TE.

Mitsubishi is something of an upstart among luxury wagon builders. The company name is reasonably well-known, in large part because of a long-standing relationship with Chrysler, but few buyers are as yet aware that Mitsubishi offers a wagon version of its Diamante sedan.

In fact, the Diamante sedan is not exactly a high-profile vehicle, either in concept or in sales figures. That's not to say that it's unattractive. In many respects, the big Mitsubishi 4-door is a class leader, scoring points for comfort, performance and manufacturing quality. The simple fact of the matter is that word of the Diamante's many virtues just hasn't gotten out to the public yet.

What's true for the Diamante sedan applies equally to the wagon. It's an extremely pleasant vehicle, competitive in just about every respect with its more familiar opponents such as the Camry and the Sable.

The fact that the Mitsubishi brand name may lack the panache of some ritzier badges shouldn't deter potential buyers from checking out the features of this entry-level luxury wagon.

Mitsubishi designers have chosen to give the Diamante Wagon an understated, formal appearance that could be perceived as conservative. There are no visible concessions to aerodynamic efficiency here. From its upright front end to its sculpted sides to its traditional station wagon roof line, the big Diamante exudes class. Few wagons, expensive or otherwise, match its subtle elegance.

Fit-and-finish details are strong Diamante selling points as well. Mitsubishi doesn't cut any corners on quality of materials or assembly. The Diamante is very well-built.

All four doors are large enough to offer easy access to the passenger compartment, and the rear hatch has a low liftover height, making loading of bulky items into the cargo space easy. A sturdy luggage roof rack is standard equipment.

This wagon borrows most of its hardware and trim from the basic Diamante ES sedan (now only available for fleet sales). Power is supplied by a V6 engine rated at 175 hp with a 4-speed electronically controlled automatic transmission. Traction control is available in the LS sedan, but it's not offered here.

Front suspension, steering and brakes are also the same as the ES sedan. Only the rear suspension was designed especially for the wagon: It's a beam-axle design to keep the load floor as low as possible.

From first glance, the interior of our Diamante test wagon impressed us. Every detail seems to have been worked out with special care, from the shape of the door handles to the sweeping curve of the dashboard. The overall impression is one of solidity and quality.

Even the wood accents, which many manufacturers tend to cover with overly glossy clearcoat, are muted.

Lots of comfort is included on the Diamante menu as well. There's room for five on front bucket and rear bench seats, though the three in back should be good friends. The driver and front-seat passenger are each protected by an airbag.

Automatic climate control is standard, as is almost every power assist one might reasonably ask for, with only power adjustment of the driver's seat relegated to the options list as part of a leather upholstery package.

The driver's environment was designed with comfort in mind. A height-adjustable steering wheel is standard, instruments are large and clearly marked (though one might expect more than the basic speedometer, tachometer, fuel and temperature gauges in a $30,000 car), and all controls are logically placed for optimum access. Visibility is good, thanks to an abundance of glass and thin roof pillars.

In keeping with the Diamante's luxury status, an excellent sound system serves as standard equipment. The AM/FM/cassette system offers up seven well-placed speakers and controls mounted on the steering wheel. Diamante's only audio option is a single-disc CD player.

Only a couple of interior details could stand improvement: Long-legged occupants may wish for a little more thigh support from the front-seat cushions, and the climate-control system would benefit greatly from some simplification of its dials and buttons. Everything else was more than acceptable as is.

Based on looks alone, you might expect the Diamante Wagon to be a most competent touring car. That's exactly what it is.

On the road, our Diamante's biggest asset was its refinement. The engine was smooth and virtually inaudible at most operating speeds. The transmission's performance was equally seamless: It shifted with uncanny precision, constantly adjusting to suit driving conditions.

Despite its calm demeanor, the Diamante Wagon is far from slow. It scoots along with ease, empty or fully laden, and cruises comfortably at any sensible speed. Fuel economy is good, too, as most drivers should be able to improve on the EPA figures of 18 mpg in the city and 24 mpg on the highway in real-world driving.

The Diamante strikes a nice balance between roadholding and ride comfort. It doesn't quite match its European competition in responsiveness, having softer springs and steering that's not quite as precise, but we don't think it will disappoint its intended customers. The Diamante Wagon is at its best during long runs over reasonably smooth and even road surfaces.

The 4-wheel disc brakes provide excellent stopping power and seem capable of absorbing hard, repeated usage without fading or pulling to one side. Our test Diamante was equipped with optional anti-lock brakes (ABS), which should be considered essential.

Although the Diamante Wagon has a lot going for it, it is expensive. The base price of more than $28,000 seems high (al-though the long list of standard features offsets sticker shock to some extent), and the few options that are available will run the tab up quickly. At a minimum, you'll want to order the ABS, which adds almost $2000 to the total.

Ordering the other four extras (CD player, leather upholstery, sunroof and remote keyless entry system) will push the Diamante Wagon's tab up toward $33,000 even before taxes and license fees are figured in.

Granted, Mitsubishi touts the Diamante as an alternate choice to luxury class offerings from BMW, Mercedes and Volvo. That's pretty high-class company and, if you perceive the Diamante as a member of this clan, the high price seems more than reasonable.

That seems to be a perceptual stretch, though. And more realistic comparisons - with the Camry and Sable wagons, for example - put the Mitsubishi at a price disadvantage that its comprehensive standard equipment list doesn't quite counter.

In the end, as always, it's a question of money and how much of it you're willing to spend. There's nothing wrong with the Diamante Wagon, and much to praise. Whether it's good enough to justify the cost is a matter for you and your checkbook to decide.