Used 2003 Audi RS 6 Sedan

Jay Leno has a motorcycle with a helicopter gas turbine engine somehow stuffed into its spindly aluminum frame. According to Leno, launch isn't much to talk about, but once spooled up the turbine seems to process never-ending boost, relentlessly accelerating at an increasing rate the faster it goes.

That same ability to defy the laws of physics pretty much sums up Audi's new RS6. The heart of this incredible Audi (the addition of the R before the S means that it is part of the company's ultimate performance version) is a new engine under the hood. Essentially, Audi took one of its already spunky 4.2-liter, dual-overhead camshaft, five-valves-per-cylinder V8s and lobbed a couple of turbochargers onto it (as well as twin intercoolers) to produce 450 horsepower.

Acceleration should always be so instantaneous and endless. Audi claims that the blown 4.2 engine reaches its torque peak of 415 pound-feet below 2,000 rpm and maintains it all the way to 5,600 rpm. That means that, at any engine speed and in any gear, the RS6 lunges ahead with ferocity usually reserved for the opening five seconds of an ultimate fighting cage match.

Make no mistake. While other Audis, including the all-new high-performance S4, are sophisticated (and rapid) sports cars, the RS6 is a beast. Oh sure, it'll poodle around town with hardly a burble from its twin exhausts and cruise the motorway with a slightly stiffer than normal ride, but for all intents and purposes it's as smooth as mainstream Audis.

But mat the throttle and all hell breaks loose. A low-frequency shudder passes through the chassis as all that torque makes its way through the all-wheel-drive system, the engine note turns as baritone as Barry White in full croon and the RS6 leaps ahead as if slammed in the rear bumper by a hurtling meteor. The RS6 has passing acceleration exceeded only by the mighty Porsche Turbo. Incredibly, its initial acceleration, measured by Audi as a very quick 4.6 seconds to 60 miles per hour, pales in comparison to its ability to relegate slower moving traffic to yesterday's news. Credit the 0.8 bar of turbo boost or the high-for-a-turbocharged-engine compression ratio of 9.8-to-1. This is one bear of an engine deserving of respect from even the most experienced driver.

And crazily enough, that really is the tip of the iceberg. Audi's contention that the V8 maintains its 415 pound-feet maximum torque across such a wide rev range means that the company has had to severely limit boost. Indeed, the engine controller regulates both boost and ignition timing to make sure that the engine doesn't put out too much torque. Otherwise, one suspects the transmission would frag itself.

In fact, the RS6's one performance weakness comes from a sense of Audi's normally robust five-speed autobox feeling challenged to accurately put all that twist to the pavement. Get on the gas quickly after having backed off and the subsequent downshift is anything but smooth. Those thinking of hot-rodding an RS6 with an aftermarket "chip" will have to be mindful of the tranny's limitations.

Audi does ensure the chassis is up to the task. The RS6's front ventilated discs are gripped by massive Brembo eight-piston brake calipers. Likewise, the suspension is controlled by Audi's Dynamic Ride Control (DRC) system, a semiactive mechanical-hydraulic suspension system. Under hard cornering, DRC stiffens the compression damping of the outside shocks while simultaneously reducing the stiffness of the inside dampers.

On the road, it all holds together admirably. The motor lunges ahead, the suspension keeps cornering flat, the 255/40R18 performance radials have plenty of grip and the brakes make short work of excess speed. We tested the RS6 on the same track as the S4, however, and it proved an abject lesson that light weight can make up for all the technological advancements in the world. Although it couldn't match the RS6's straight-line speed, the S4 could whip the RS6's 4,024-pound butt in the twisty bits despite its theoretically inferior suspension and brakes. As well, the automatic transmission is easily confused and often in the wrong gear despite its Tiptronic manual-shifting mode. The RS6 was never meant for such abuse, but when kept in its intended environment or high-speed cruising on wide, flat roadways, it's quite amazing.

As for more pedestrian duties, the RS keeps with most of Audi's A6 abilities. Unlike the S4, the rear accommodations aren't overly cramped. However, I would have preferred the smaller Audi's Recaro front seats. They provide much better side bolstering and were far more attractive with their colored Alcantara inserts. The RS6's seats are more muted, with monochromatic gray leather, for instance, highlighted by white piping. It's meant to appeal to the older, more conservative crowd who can afford the RS6, but anybody buying this car, regardless of age, is defining him or herself as young at heart.

Speaking of price tags, the RS6's is expected to ring in around $85,000. That's serious coinage, more than BMW's class-defining M5, in fact. Besides the conservative cabin decor, my one condemnation of the RS6 is that the company seems to have once again put the cart before the horse in the pricing sweepstakes. Audi desperately wants to be mentioned in the same breath as BMW and Mercedes-Benz, but before it can start charging the same price for its products it must first establish a reputation equal to the task.

The RS6 may indeed be the equal of BMW's M5, but I think it will be some time before public perception catches up. Charging more than the class' benchmark right out of the gate certainly takes some serious cojones.