When Saab introduced the 9-5 at the North American International Auto Show in Detroit in January, I didn't spend much time lingering around the company's display.

After all, I'd seen it all before, right?

There was yet another permutation of the familiar Saab styling cues, on the grille, the taillights and the general shape of the car. Nothing that would quicken one's pulse or turn a head.

Well, it turns out a book isn't the only thing that can't be judged by its cover.

Underneath the 9-5's cover -- the body, that is -- lurks one of the most technically excellent engines and finely tuned suspension systems you can buy. The 9-5 may look like something a well-to-do 1990s Ward Cleaver-type might drive -- but don't be fooled. Saab engineers have leaned on the company's aircraft heritage and created a car that flies on the ground.

PERFORMANCE, HANDLING

In the 9-5, Saab has brought some real innovation to the good, old internal combustion engine. Saab engineers did it with a unique application of the turbocharger.

The turbocharged, 3.0-liter V-6 in the SE makes 200 horsepower. Unlike other turbocharged engines, the Saab's turbo runs all the time. It's built into the front cylinder bank's exhaust manifold and it provides a small, steady amount of boost.

You might remember that a turbocharger is an exhaust-gas-driven pump that crams a denser mixture of fuel and air into the engine. On regular turbocharged engines, a device called a wastegate opens when the throttle is pressed down hard. Once the wastegate opens, the exhaust gases flow past the turbocharger, which begins to spin at very high rpms. The turbocharger then pumps air and fuel into the engine. Because all this takes time, the driver feels ``turbo lag'' -- the car pauses for a second or two before the power comes on.

Saab engineers have solved the turbo lag problem, and, in the process, have created a lively engine that pours on the power and keeps it coming with no peaks or valleys.

If you step on the accelerator in the 9-5, you better make sure there's nothing in front of you. The base model 9-5 comes with a 2.3-liter, four-cylinder engine that uses the same turbocharging system. It makes 170-horsepower.

Our black 9-5 was outfitted with a four-speed automatic transmission, which drives the front wheels. It performed like a rocket-sled on rails. The ``S'' (sport) button on the shifter made the car even faster. Pressing the button not only makes the transmission shift later but also electronically changes the engine's throttle response time. The 9-5 is a ``drive-by-wire'' car, meaning the accelerator is connected to the engine electronically.

The 9-5 uses a McPherson strut, four-wheel independent suspension system front and rear. The car has a wonderfully athletic feel. The power-assisted steering is crisp, tight and responsive.

The suspension system is mounted to an extremely rigid body structure, making the 9-5 feel as if it were carved o ut of a single block of steel. The body doesn't lean when you round a corner at high speeds. The four-wheel, power-assisted, anti-lock brakes are excellent.

FIT AND FINISH

A Saab wouldn't be a Saab without a little quirkiness.

The ignition switch is still on the floor near the shifter. And the interior has a feature or two I've never seen before. But I like this car.

For instance, the seats have perforated leather, and those holes are not just there for decoration. Two small motors in the seat assembly draw air through the holes. This keeps hot air from being trapped between the driver's and passenger's bodies and the upholstery. The seat air circulation system is optional in the 9-5. The system has been around for years and has been shown to improve driver alertness in buses and trucks. But this is the first time it has been used in a car, according to Saab.

Unlike the 9000, which it replaces, the 9-5 is a four-door sedan, not a fi ve-door hatchback. Yet S aab still has managed to build an incredible amount of versatility into the 9-5.

The bottom part of the rear seat cushions fold forward, and the top part folds down. This gives the car an unusual amount of interior cargo room. But even with the seats folded up, there still is enough room in the trunk to store three golf bags.

The 9-5's dash is stylish and user-friendly. All the buttons and switches for the air conditioner, radio and lights are within easy reach. The analog gauges are easy to read.

Saab equips the 9-5 generously. The car comes standard with a CD player, sunroof, cruise control, power seats with memory, radio-controlled door locks, alarm system and more.

Nice touches includes a super nifty, dash-mounted cup-holder that slides smoothly out and then twists as it unfolds; a button on the mirror switch that tilts the left-side rear-view mirror down when the car is in reverse; and steering wheel controls for the radio.

The interior is tastefully adorned with shiny wood trim. Saab engineers believe the 9-5 will emerge as one of the safest cars on the road, once some real-world accidents occur and can be studied. It has energy-absorbing front, rear and side crumple zones and four air bags.

Saab also believes the 9-5 will gives Lexus a run for the money when it comes to quality, reliability and dependability.

I think the 9-5 has a sporting chance. After about 500 miles, I am inclined to place the new 9-5 in a very elite group of cars: It's one of the best mid-size performance sedans you can buy.

The boys at Lexus, Acura, BMW and Mercedes now have catching up to do.

1999 Saab 9-5 SEBase price: $36,800.Safety: Dual front and side air bags, traction control, anti-lock brakes and side-impact protection.Price as tested: $38,400.EPA rating: 18 mpg city/26 mpg highway.Incentives: None.