When all driving is done and our judgmental seat backs are returned to their upright positions, there really is only one firm way to evaluate a car: On memories that linger.

Looking back on a week and 800 miles with the Infiniti G20--another in the vogue of the entry-level car from luxury lines and rather like a nongolfing membership at the Lakeside Country Club--one recalls a spirited vehicle that is close to delightful for several reasons.

Cab forward design of this mini Infiniti. The front deck is short and the rear deck is stubby because the design demanded optimum head and leg room from an elongated, roomy passenger cabin. And it works, this squeezing of a quart from a pint pot, with barely a whisper of snubbiness. You also get 105 cubic feet of room, which is only 8 cubic feet tighter than a 1991 Cadillac Seville.

Happy handling. With a multilink suspension adapted from the Nissan 300ZX (a variety of control arms that keep tires flat and grabby on the road despite the wheel-warping forces of cornering, braking and acceleration) the Infiniti G20 is among the sweetest handling road cars this side of the Monte Carlo Rally.

Sticker pleasantness. At a base price of $17,500, the four-door G20 certainly undercuts entry-level models from Mercedes (the 190E at $28,000) and BMW (the 318i at $20,000) and archrival Lexus (the LS250 at $21,500) and, frankly, it outperforms all of them.

Now the lesser news.

The Tiffany Quotient. To consider (as Infiniti does) the G20 as a "luxury sedan" is to fall for a misnomer. Luxury connotes largeness and an expanse of creature comforts and the G20 is a mid-size car bordering on the compact. It just isn't spacious enough to exhibit too much of anything luxurious. No matter the quality of trim (and it is very high and well crafted on the G20), leather seat surfaces get lost. There isn't a toothpick of wood trim anywhere because in a condensed car, walnut facing would fade to slivers and token opulence.

Styling. Visually, the curves and sweeps of the G20 are about as generic as Ronzoni macaroni. Park it in a lot loaded with Honda Accords and Geo Prizms and you'd better look for it by color and whatever you left on the front seat. Therein lies the penalty of today's slavery to wind tunnel designs--cars have become contour cousins moving closer toward mutual invisibility.

Mechanicals. Much of the G20 is borrowed from the Nissan Stanza and that includes a four-cylinder engine that gets somewhat raucous when asked to perform above and beyond the calls of standard freeway duties. Yet in truth, one is reluctant to say anything negative about the G20 because of the incredibly hard road Infiniti has driven in what should have been an even-Steven competition with Lexus in theluxury car category.

Lest we forget.

Lexus, a Toyota subsidiary with a two-car line topped by the $39,000 LS400, was la unched in August of last year. Infiniti, a Nissan division with the $38,000 Q45 as its lead luxury car, came along three months later.

The tardiness of Infiniti was compounded by a fatuous advertising campaign that droned on for weeks about man's oneness with twigs and rocks. It forgot to show the car, and that fine faux pas minted more monologue jokes than Donald Trump.

Lexus was lauded. Infiniti was just as flawless--but quickly fell on its nose in a market that traditionally buys first and works comparisons later.

Numbers tell the damage. In the January-September sales period, Lexus sold 45,400 cars. In the same months, only 15,000 Americans purchased Infinitis.

Will the G20 help adjust the imbalance?

Infiniti thinks so.

For in its first full month of October, said a spokesman, almost 1,000 G20s were sold--or 50% of the 1990monthly sales average for the LS250, its entry-level Lexus rival.

On the other hand, will the G20 tri over its half-brother, the Nissan Maxima, which offers much the same configuration, at much the same price, and much the same performance--but from a tougher V6 engine?

Infiniti doesn't think so.

The Maxima, continued the representative, is not considered a luxury car. The G20 is. That means a fatter program of perks--the current buzz phrase for that being halo effect--which includes 24-hour road assistance, broader warranties and much bowing and scraping at Infiniti dealerships where everyone wears kid gloves and the customer is always perfect.

Infiniti did not leave too many continents unturned in its desire to find that little bit extra. In an industry where more than three dozen companies are marketing several hundred models, digging deeper is what you do to stay alive.

So Infiniti G20 researchers came to the United States to plumb our interpretations of classy versus tacky. They then took their car to Europe for some comparative testing on the Nurburgring racing circuit against others in its class.

Such diligence shows in the subtle appointments and superior performance of the G20.

The interior--from sharp white numbering on large black instruments, to dashboard buttons big enough for fat thumbs--is precisely what we have come to expect from the Asian imports. Perfection. And then some.

Such as power window controls in door pulls/armrests that bring a pistol-grip feel to the function. Such as every vent, lever and switch being within the reach of a 6-year-old with short arms. And remote catches (also in the arm rest) for the trunk lid and gas cap and both function with the ignition off.

Visibility is excellent with absolutely no encumbrance from door and window pillars. Although one day, we must pray, some engineer will win the design battle that will rid us of rear blind spots forever.

There is enough headroom for a six-foot driver wearing a crash helmet and miner's light.There is sufficient seat room for back-seaters to ride around town without knees beneath their nostrils. Elbow room is XXL.

As is the custom with luxury carriages, the list of standard equipment reads like an inventory of options on other cars. And the G20's only options are a power sunroof, CD player, leather-faced seats and marble fireplace.

The power plant is a 16-valve, two-cam, four-cylinder engine producing 140 horsepower. Although a buzzy little guy, it is quick enough to match the Mazda RX7, the BMW 318is and the Audi Quattro Coupe in initial acceleration. It is willing to propel the car purposely at just about any point on the performance curve.

But it is in its handling--that frequently botched harmony of steering, brakes and suspension--where the Infiniti approaches infinity.

Straight line acceleration is quick and clean. Even heavy applications of power when exiting a turn produce only a mild twitch of torque steer with no need to fight the wheel.

On or off center, on or off limits, steering feedback tells hands all a driver needs to know about the positioning and adhesion of wheels and tires. Corrections produce immediate response with no great disasters indicated if those hands turn out to be a little hammy. And once on its line, the steering set is faithful and wheel pressures almost fingertip.

The brakes--10-inch discs on all wheels with an anti-lock system (ABS)--stop well. When stomped, they produce only subdued groans and pulsing from the computer-tamed ABS.

Introduction of the G20 swells Infiniti to a three-car lineup, four if you count a convertible version of the 3-liter, V6-powered M30.

Lexus, meanwhile, is standing pat for 1991 with two cars virtually unchanged from last year's debut.

It could well be Infiniti's turn at bat.

1991 Infiniti G20

The Good High quality interior, top drawer fit and finish. Amplepower with crisp handling. Priced right. Optical illusion of small exterior, large interior.

The Bad Vanilla styling.

The Ugly Brown and cream interior, fit only for Tom Wolfe's wardrobe.

Cost Base: $17,500 (with five-speed manual transmission). As tested: $19,550 (includes power sunroof, leather-faced seats and delivery charges).

Engine Four-cylinder, 16-valves, twin cam developing 140 horsepower.

Type Four-door, four-place, luxury sedan.

Performance 0-60 (as tested) 9.1 seconds. Top speed, estimated, 130 m.p.h. Fuel economy, EPA city-highway, 24 and 32 m.p.g.

Curb Weight 2,800 pounds.