2004 Audi RS 6 There are moments when driving becomes everything it is supposed to be -- fast, precise, artful, exciting. They are rare occurrences, epiphanies. They happen in special cars, such as Audi's RS 6 sedan, which enters 2004 unchanged from its introduction last year. Only 860 RS 6 models are available in the United States, which means they are exclusive and expensive cars for the rich. It is a circumstance that defines luxury -- the ability to buy and enjoy generally unobtainable items and experiences. Lexicographers say luxury also involves the acquisition of unnecessary things. But on that point, in the matter of the RS 6, I disagree. Time behind the wheel of a superbly tuned automobile is as necessary for a car lover as time in front of a brilliant orchestra is for a lover of music. Both car and orchestra have much in common. They are collections of seemingly disparate parts and notes brought together for memorable performances. Consider the RS 6's engine. It is derived from the 4.2-liter V-8 in the Audi A6 all-wheel-drive sedan, which delivers 300 horsepower at 6,200 revolutions per minute. But 300 hp is common fare nowadays. Exclusivity demands more. Audi got more from its Quattro GmbH performance group, which fitted the 4.2-liter V-8 with twin turbochargers to ram more air into its combustion chambers. That extra boost helped lift the engine's horsepower to a maximum 450, delivered between 5,700 to 6,400 rpm. Torque, the force generated by the engine to turn the car's drive wheels, is even more impressive. The RS 6's V-8 produces 415 foot-pounds of torque between 1,950 to 5,600 rpm. Thus, very little gas-pedal pressure is needed to get the car going. When it moves, it does so with blistering authority. Audi engineers say the RS 6 can go from 0 to 60 miles per hour in 4.9 seconds. I have no reason to argue with that. Legal prudence requires that I say little else. The RS 6 is remarkably swift for a car with a curb weight -- weight without driver, passengers or cargo -- of 4,024 pounds. It feels lighter, tighter and faster than many high-powered sports coupes. Certainly, the RS 6 feels more nimble, largely because of its four-wheel-independent suspension system and its all-wheel-drive running gear. The car remains sure-footed on grooved and rutted urban streets; and it dances nicely on gravel roads, too. Enlightenment came during one of those moments of movement on a post-midnight highway uncluttered by traffic. I found myself alone with the car and its baritone exhaust note, humming through the darkness. The instrument panel was aglow with soft, red lights. The Bose 200-watt AM/FM/six-disc, in-dash sound system was off, and I was smiling. It was just the idea, the feeling of being behind the wheel of all of that power, of getting it to r espond to me with each touch of the accelerator, each slight turn of the steering wheel. I was the conductor. The RS 6 was my orchestra, and it was playing beautifully. Nuts & Bolts Downside: The RS 6's base price tag is $82,700, substantially more than that of the upcoming 2005 BMW M5 ($73,195) and the 2004 Mercedes-Benz E55 AMG ($77,650), both of which have more prestige than Audi. And with 469 hp in the E55 AMG, the Mercedes-Benz car has more horsepower than the RS 6 as well. Rich people love exclusivity; but they also attach value to the label. Also: Complaints and worries about Volkswagen/Audi service quality persist. Make sure that the dealer who sells you this one has the technical competence and equipment to repair it. Ride, acceleration and handling: Superior in all three categories. What else would you expect from a sports car with an $82,000-plus price tag? Head-turning quotient: Extremely high among Audi aficionados. But t e rest of the public gave it little attention: Those on the outside of the inside track generally regarded the RS 6 as a $30,000 car. Capacities: The RS 6 has seating for five people. Cargo capacity is 15 cubic feet. Fuel capacity is 21.7 gallons of gasoline. Premium unleaded is required. Ground clearance for the RS 6 is 4.1 inches. Layout/design: The RS 6 is a front-engine, all-wheel-drive luxury sedan (four doors). Engine/transmission: The car's 4.2-liter, 450-horsepower, 40-valve, twin-turbo V-8 is linked to a standard five-speed automatic transmission with overdrive. The transmission can also be operated manually. Mileage: I averaged 20 mpg in mostly highway driving. Safety: Front and rear ventilate disc brakes with standard anti-locks; side air bags for front seat passengers; head air bags front and rear; emergency brake assistance, traction control, child-safety seat anchors. Price: Base price is $82,700. Dealer invoice price is $74,239. Price as tested is $84,660, including a $1,300 federal gas-guzzler tax and a $660 transportation charge. Purse-strings note: Reality has a way of kicking you in the butt. But time behind the wheel of this fine-running car is worth the dream, if you can afford it.