Under the hood, technology such as dual overhead camshafts, variable valve timing, and five valves per cylinder help the 2006 Audi S4's V-8 churn out 340 horsepower. With Audi's stalwart Quattro system driving all four wheels, the S4 remains composed and predictable, and electronic stability controls keep the power from overwhelming the tires on loose surfaces.
The face of the redesigned S4 features the signature Audi chrome-ringed grille, but the car is otherwise discreetly more masculine than the 2006 Audi A4 and pleasantly purposeful to behold. Sporting the bulging wheel arches of the new A4 but with rocker-panel cladding and a small rear spoiler, the S4 is different enough to be discernable but not showy. Our car's understated Light Silver Metallic paint ($475) fit the confident character of the styling; brighter colors will likely make the wide snout stand out more.
With an MSRP of around $46,000 and our car's as-tested price at $56,045, the 2006 Audi S4 is substantially dearer than the V-6-equipped A4, starting at about $36,000 for a Quattro. But the difference is both outwardly visible, if subtly so, and palpable from the behind the wheel. The S4's combination of performance, style, and AWD controllability is well worth the upgrade.The 2006 Audi S4 impresses with its interior, as we've come to expect from all recent Audis. Materials are good quality, design is tasteful, and the layout and feel of both the mechanical and electronic controls are highly satisfying, with the exception of the hand-brake lever. Overall, it's a minor complaint, but the driver armrest sits over the lever, requiring the former to be lifted to move the latter.
Immediately upon sitting in the bolstered Recaro sport seat and grasping the thick three-spoke steering wheel and leather-clad shifter, the driver anticipates an experience a step beyond that of the average sports sedan. The gauges are large and legible white on black, the speedo and tach separated with an information screen using Audi's usual red digital LED.
The full-color main screen for the multimedia interface (MMI) is crisp, and the system's combination of a main control knob with four surrounding contextual buttons works much better than the iDrive in the 2006 BMW 750Li we recently tested. Audi Navigation Plus ($1,950) offers clear maps, relatively simple settings, control, and display of the next route step on the smaller screen between the main gauges. A row of hard buttons beneath the screen makes switching between the various infotainment systems quick and easy.
Our car was spruced up with the Premium Package ($2,900): a glass sunroof; heated front seats; split spoke-design 18-inch wheels (different 18-inchers are standard); a HomeLink transmitter; autodimming mirrors inside and out; memory functions for seats and outside mirrors; a light- and rain-sensing system that turns on the headlights and adjusts intermittent wiper frequency; and adaptive headlights. Also checked on our car's options list was the Cold Weather Package ($400), featuring heated rear seats and a ski-sack pass-through from the trunk.
A six-CD changer resides behind the glove-box door, an arrangement we like better than trunk-mounted changers for easy loading and unobtrusiveness. Our car came equipped with the Premium Audio Package ($1,500), which upgrades the standard Audi Symphony setup to a Bose system with surround sound and a dynamic noise-compensation feature. A microphone in the cabin regulates the stereo's volume in specific frequencies to compensate for unwanted interference, such as that from passing vehicles. The sound from this system is very refined and doesn't lend itself to pumping out bass to ridiculous levels.
The 2006 Audi S4's Premium Audio Package also includes preparation for either XM or Sirius Satellite Radio, controlled via the MMI or steering wheel buttons, as with the other audio features. Also part of the package is Bluetooth phone integration. The Motorola V551 we used for testing linked with the car easily, although interaction was limited to speakerphone usage--phone book information was not displayed, and the car offered no dialing system of its own.
Our favorite of all the 2006 Audi S4's gadgetry is the SD-card reader in the dashboard. As we saw on the Audi A4, the MMI's screen tilts down and forward to reveal two slots to accept the portable media. MP3 files are read from the cards immediately, including title and artist information. We've been frustrated by the lack of MP3 player inputs for the higher-end factory audio systems we've tested of late, with a car's chance of having an auxiliary jack on the dash somehow inversely proportional to its sticker price. The ability to swap the same storage device from computer to car nicely obviates the need for the car to recognize and deal with a hardware go-between; you can just give the data to the car directly on an SD card. Music played this way sounded similar in quality to CDs or the satellite radio--Sirius, in our car's case.While the other occupants of the 2006 Audi S4 will enjoy the luxurious aspects of this car, the driver will understand the true nature of this beast. The S4 seems poised under any and all normal driving conditions, as well as some slightly abnormal ones. A feeling of utter solidity and the confidence of abundant power come together in this car, unlike with a few other four-doors.