If you think all those slick Infiniti commercials - which are beginning towear a little thin - are nothing but more ad agency drivel dreamed up by someMadison Avenue whiz kid, you are dead wrong. The Infiniti Q45 is everythingthe ads claim.

Consider Infiniti's slogan: ''The gods live in the details.'' It is in thedetails where the Q45 goes beyond excellence. You can't help but notice thingslike the placement and feel of the switches; the faces of the gauges; thesmooth way the glove compartment opens; and the ease and precision with whicheverything operates. You want details? There's even a card in the glovecompartment containing the signature of a Nissan ''Quality AssuranceEngineer'' certifying that the car has been tested and all systems are go.

On most cars you don't notice things like how the seats are adjusted or theway the air conditioner controls work. You just use them and forget it. It'snot like that in the Q45. The controls work so well and divert so little ofyour attention away from driving the car, that you can't help but notice.

Every switch, button or knob the driver touches are part of what must havebeen a complete rethink of the way cars are put together. A computer-literateperson might call the Q45 user friendly. Things that previously werecomplicated are now easy. If you want a good example of this, compare a 5or7-series BMW with the Q45. With dozens of buttons and knobs on the BMW's dash,you feel like you need a degree in engineering to figure out how to operatethe radio.

I wasn't in the Q45 for more than an hour before I was wheeling it aroundas if I had owned it for years. I never once needed to take my eyes off theroad to switch radio stations, raise or lower the windows, switch gears oradjust the temperature.

With the Q45's computer-controlled memory operating the driver's seat andsteering wheel, the car and changes the position of the seat or steering, oneflick of a button will put them right back to where you like them.

If a manufacturer puts a price of $38,350 on a car, it had better be prettyspectacular. But Nissan engineers went beyond spectacular in every area exceptthe styling.

The badge on the Q45's nose has taken a lot of heat. Comedian Jay Leno saidit reminded him of a belt buckle with snakes on it. One of the auto magazinescalled the large, gaudy badge the work of a Cadillac designer on a bad day inthe '60s.

The Q45's door handles also have been criticized for looking out of place.And the car's overall styling isn't memorable. In fact, the Q45's front endhas the same basic shape of the Ford Taurus, the new Acura Integra and half adozen other cars. Rear-seat passengers more than 6 feet tall are apt to beuncomfortable. Feet have to go underneath the front seats, and head room isbut an inch or two. The placement of the foot-operated emergency brake is alsopoor. My left foot kept banging into it. But these shortcomings are the lastthing on your mind as you are muscling down the road.

With the possible exception of the engine lurking under the hood of theTaurus SHO, there is no finer looking power plant than the 278-horsepower,32-valve heart-stopping V-8 in the Q45. It just may be the Rolex of automotiveengines.

The Q45's engine is smooth. By shifting from fourth to third on the car'sautomatic gearbox and pressing the exhilarator (the gas pedal is much morethan an accelerator in the Q45), you leap from 40 mph to 80 mph in the blinkof an eye. You don't expect that from a car the size of the Q45. You alsodon't expect it to handle the way it does, which is somewhere near perfect.

The speed-sensitive steering felt just right. Take a tight curve at highspeeds and the Infiniti seems connected to the pavement as if by some magicalmagnetic force.

Regardless of how you feel about the Infiniti's styling or about Japanesecars in general, if you are considering a luxury car, this one should not beignored. It represents state o f the art technology and engineering, a qualityof build equal to or greater than anything from Europe, and, most importantly,a value-for-money factor that few cars can match.

The test car, provided by Don Mealey Infiniti, came equipped witheverything you find in the big BMW and Mercedes-Benz cars: leather interior,sunroof, impressive sound system, anti-lock brakes and power everything. Thereis one sticker on the car. It reads $38,350. That's it. There are no hiddencharges, no gouging for rustproofing, undercoating, upholstery protection orany other dealer-added rip-off item, such as extra profit ''market valueadjustments.''

You can buy a cellular phone for about $1,200, a CD player for another$1,100 and a touring package for about $2,500 more. Those are the only optionsavailable.

With the Q45, the warning shots have been fired. The Japanese already ownthe economy car segment of the market. If the European automakers don't watchtheir flanks, they may be overtaken - if they haven't been already.