Used 2006 Audi S4

Though not quite as enthralling as BMW's frenetic M3, the 2006 Audi S4 still offers entertaining performance along with a more livable personality.

Much in the way that BMW has its pumped-up "M" cars and Mercedes its AMG-massaged land jets, Audi has its tweaked "S" versions of its vehicles. Although the previous-generation S4 packed a twin-turbo, 250-horsepower V6 under its hood, Audi didn't think that was enough for the latest overachieving A4. The current-generation Audi S4 -- available as a sedan, wagon or convertible -- ups the ante with a muscular 4.2-liter, 340-horsepower V8 powering all four wheels.

The Audi S4 has certainly moved up in the performance ranks with the addition of the V8. Even with a pair of turbos, the previous V6 was no match for eight high-revving pistons. Moreover, Audi was determined to beat the M3 in the spec sheet race and continued to massage the 4.2-liter engine until it surpassed the Bimmer's 333-hp rating. With 340 hp screaming out at a heady 7,000 rpm, the S4 loves the upper end of its rev band. Of course, a few tweaks were needed to match the chassis to the prodigious power plant. A tightened-up suspension along with 18-inch high-performance tires help to make the most of the powerful V8 and Audi's quattro all-wheel-drive system.

Far from being a one-dimensional car, the Audi S4 also provides a comfortable and functional cockpit -- for example, in the sedan and wagon models the ultrasupportive front buckets are 12-way adjustable Recaros covered in what Audi calls Silk Nappa leather. Elsewhere, you'll find the fine-quality materials and upscale conveniences that make the A4 family the most luxurious among all entry-level luxury cars. The S4's most noticeable shortcoming is endemic to the entire A4 lineup, namely the lack of rear-seat room. Now that virtually all Japanese sedans have spacious rear accommodations, and most European competitors have at least paid passing attention to the needs of those relegated to the back, the S4's lack of rear legroom might be off-putting to some enthusiasts with families.

Still, the fact that you can get the Audi S4 as a sedan, wagon or convertible body styles gives it an edge over the BMW M3. Apart from the rear accommodations, the S4 is a thoroughly entertaining and comfortable choice. Audi's decision to price the S4 within shouting distance of M3 and Mercedes' C55 AMG takes some serious chutzpah, but at least the Audi car has the specs to back it up. Shopping for a high-performance sedan, wagon or convertible this year? You'd be making a mistake if you didn't take the 2006 Audi S4 for a spin before making your decision.

The Audi S4 is available as a sedan, wagon (Avant) or convertible (Cabriolet) in one well-equipped trim level. Standard features include 18-inch wheels and tires, HID headlights, 12-way power-adjustable Recaro seats, Silk Nappa leather upholstery, dual-zone automatic climate control, heated mirrors and a 10-speaker audio system with an in-dash CD changer. Convertibles are equipped with more conventional leather-upholstered sport seats in place of the Recaros, along with a power-operated soft top. Among the available options are an upgraded 215-watt Bose stereo and a navigation system. A limited run of 250 "25quattro" editions celebrates 25 years of Audi's all-wheel-drive system. Carbon-fiber accents on the front and rear spoilers, 18-inch multispoke DTM wheels, silver paint, a gray and black interior scheme with carbon-fiber trim and a special shift knob mark the 25quattro, which also comes loaded with satellite radio and the navigation system.

All S4 models are fitted with a 4.2-liter, 340-horsepower V8 that channels the power to Audi's quattro all-wheel-drive system through either a six-speed manual gearbox or a six-speed Tiptronic automatic. The latter transmission allows manual-style shifting via steering wheel-mounted paddles. Audi claims that an S4 sedan equipped with the manual tranny can sprint from zero to 60 mph in 5.3 seconds.

Safety features include a superb set of four-wheel antilock disc brakes, Electronic Brakeforce Distribution, BrakeAssist and stability control. Additionally, the Audi S4 is equipped with side airbags for the driver and front passenger. There are also side curtain airbags for the front and rear; seat-mounted side airbags for the rear are optional. In government crash testing, the A4 sedan on which the S4 is based received five stars (the highest rating) for front-seat occupants in the side-impact category and four stars for the rear. And in frontal-offset crash testing, the Audi car earned the highest rating of "Good" and was named a "Best Pick."

As one would expect, with a 340-horse V8, performance is thrilling, and on winding back roads, the S4's top-notch underpinnings result in excellent handling while still providing a supple ride. While the 2006 Audi S4 isn't quite as razor-sharp as the M3, the extra grip afforded by its all-wheel drive could justify the trade-off for many enthusiasts, particularly those who live in parts of the country where rain- or snow-slicked roads are a part of life.

Audi interiors are some of the finest in the luxury car arena; one look at the S4's cabin and the high quality of materials used is quickly apparent. Tasteful accents abound, such as brushed aluminum trim and gray instrument facings. The serious performance intentions of the Audi S4 are reinforced by standard Recaro front seats in the sedan and wagon, which feature aggressive bolstering to hold one in place during spirited runs through the twisties. Although the rear seat is fine for small children, adults seated back there will likely complain about a shortage of legroom. The Avant wagon provides up to 61 cubic feet of cargo space with the rear seats folded.