How many ways can an auto manufacturer repackage the same basic vehicle into new configurations that then allow its marketing gurus to proclaim the latest version to be "the world's first . . ." whatever.

Actually, I don't have the answer to that question, it's still a work in progress, but Subaru is clearly the front-runner, and there is no indication that it will quit mining that niche anytime soon.Nor should it. If it ain't broke, as Subaru spokesman "Crocodile Dundee" might put it, don't fix it, and the car division of Japan's Fuji Heavy Industries, after years of being broke, has mended itself nicely by concentrating exclusively on four-wheel-drive vehicles.

The Subaru Outback station wagon - "the World's First Sport Utility Wagon" - is now a certified hit. Subaru took its rather pedestrian Legacy four-wheel-drive wagon, beefed it up into a brawnier package and sent it out to do battle with Explorers, Cherokees and Blazers, where it has acquitted itself quite nicely.

So nicely that Subaru of America had its best month ever in May with total sales of 12,280 units, a hefty 28 percent increase over May 1997, the best May in 10 years and the fifth consecutive month of sales growth. It is expected that June sales will prove to be equally strong when those numbers are released.

Which brings us to this week's ride, the 1999 (Happy New Year!) Subaru Legacy Sport Utility Sedan or SUS for short. And, yes, it's being billed as "The World's First Sport Utility Sedan." Big surprise.

And maybe inaccurate as car buff magazine Car and Driver noted in its June issue, pointing out that the late and unlamented AMC Eagle line of sedans, coupes and wagons had four-wheel drive way back in the late 1970s before the term sport utility vehicle was even coined.

But who cares. I wouldn't have been caught dead in an AMC Eagle back then, and not many folks were willing to be caught alive in them, either, since AMC went the way of Hudson, Studebaker and Nash, among many others. (Chrysler, which bought AMC, carried some Eagle models along, but they didn't do much better than they did with AMC.)

But the Subaru SUS is another story. The Knudson household proclaimed the glacier white SUS a winner the moment we laid eyes on it, and our appreciation of its virtues only grew over the week that it graced our driveway. "I love this car," proclaimed my wife, Karen, who is currently driving a 1990 Subaru Legacy wagon (purchased the summer of 1989) that has 126,000 miles and is finally starting to show its years.

The loaded '99 SUS Ltd has quite a few items that our '90 Legacy does not, however, most noticeably automatic transmission, leather seats, anti-lock brakes and air bags. Still, it's pretty much the same car; same 4wd drive train, same four-cylinder "boxer" engine (although the SUS' engine has a bit more displacement).

What isn't the same is the price. We paid $16,000 and change for our '90; the '99 SUS has a bottom line of $26,090, including the $495 delivery charge. There were no options; an array of comfort, convenience, safety and luxury stuff are all standard on the Limited edition of the SUS.

Fuel mileage is rated at 21 mpg in city driving and 26 mpg on the highway. This is not heroic gas mileage for a four-banger, but it's a pretty big four-banger (2.5 liters) and it's pushing a fairly heavy car (3,160 pounds).

Four-wheel-drive vehicles have never been econocars, but the SUS is vastly superior in fuel conservation when compared to many other sport-utes, particularly the Toyota Land Cruiser, Range Rover County and Lincoln Navigator to name three of the more profligate gas guzzlers.

Does the Subaru Legacy Sedan work as a sport utility vehicle? Not as well as the Outback wagon - a sedan simply doesn't have the utility of a wagon to really qualify as a sport utility vehicle - but it certainly is sporty enough. For those who want four-wheel-drive and a bit of macho flair but just can't abide the idea of driving a station wagon (too closely linked to mom, kids, grocery shopping and soccer practice), the SUS may be their ticket to ride.

For the record, Subaru doesn't expect the SUS to boost sales like its Outback and Forester sport-utes have done. Sales projections are for a very modest 3,600 SUS models per year.

How do you convert a Legacy sedan into the world's first sport utility sedan? Glad you asked. First, you add a hood scoop and trunk-lid spoiler and two-tone paint (my white tester had slate gray paint along the lower body cladding; a nice contrast). Then you beef up the bumpers for bushwhacking and insert sexy Paris-Dakar fog lights into the front bumper.

Finally, you put big 15-inch aluminum wheels all around and shod them with beefy Michelin XW4 tires that, along with a slightly raised suspension, gives the SUS 7.3 inches of ground clearance, sufficient to clear rocks that would dent the oil pan on the regular Legacy sedan.

On the inside, you continue the outdoorsy theme with a weather-band radio, split/folding rear seatbacks that accommodate skis, snowboards and other such gear, and you heat the front seats, outside mirrors and rear window.

To assure that the SUS wants for nothing that the big boys in their Expeditions and Tahoes have, you add a power glass sun roof/moon roof, a CD player and the aforementioned leather seats.

Voila! The world's first . . . well, you know.