Used 2015 Audi S4

Offering understated styling and confident, ultra-refined performance, the 2015 Audi S4 remains a top choice if you want a nimble luxury sedan with a little extra kick.

Would you believe that this is the sixth year of production for the current-generation Audi S4? That's what subtle styling will do for you. Eschewing trendy swoops and creases, the S4's designers didn't stray far from the regular A4 sedan's formula, adding only special wheels, quad tailpipes, silver mirror housings and a gray grille. As a result, the 2015 Audi S4 has a timeless elegance to it, accented by up-to-date LED lighting elements but fundamentally defined by class and restraint. Not everyone wants to advertise their car's performance potential to the world, and in this regard the aging S4 is still a breath of fresh air.

Speaking of performance, the S4's sublime supercharged V6 hasn't aged a day. When it debuted, the S4 was slightly quicker than its main rival, the BMW 335i, and that continues to be the case six years later, even though the 3 Series is now in a new generation. We initially gave the all-wheel-drive S4 a slight edge in handling, too -- particularly with the optional sport differential aboard -- and that margin has actually widened with the softening of the latest 3 Series. As for available transmissions, the S4's gratifying six-speed manual shifter can be swapped out for Audi's seven-speed dual-clutch automated manual, a.k.a. S tronic, a nearly flawless gearbox that's one of the best in the business at any price.

So how can you tell that the S4's the old guy? Answer: Bluetooth audio isn't standard, and it comes only with the pricey Technology package. That wouldn't happen in a new model these days. We also expect Audi to ditch the inferior dash-mounted MMI (Multi Media Interface) controller when the next S4 comes around, as most S4s are outfitted with the upgraded console-mounted controller anyway. But otherwise, the S4 is as appealing now as it was when we first met, and that's a real testament to Audi's engineering chops. You can find plenty of newer options in this segment, but good luck finding a better one.

Headlining the list of alternatives is the 2015 BMW 335i referenced above, which is indeed less thrilling than its predecessor, but nonetheless merits a close look given its exceptionally well-rounded skill set. The 2015 Lexus IS 350 comes up a bit short in the performance category, but its striking looks, stunning interior and willing V6 make it a worthy adversary. But you know the 2015 Audi S4 will look and drive great as long as you own it, and that could be enough to seal the deal.

The 2015 Audi S4 is a high-performance version of the A4 luxury sedan. It's offered in a single Premium Plus trim level, with an available Prestige package that adds a number of high-end features.

The Premium Plus includes 18-inch wheels with summer performance tires, selectable drive modes (Audi drive select), a sunroof, automatic xenon headlights with washers, foglights, LED running lights and taillights, automatic wipers, quad exhaust tips, auto-dimming mirrors with exterior heating, keyless entry and ignition, tri-zone automatic climate control, heated eight-way power front sport seats (with four-way lumbar adjustment), driver memory settings, leather and simulated-suede upholstery, a 60/40-split-folding rear seat, aluminum interior accents, Bluetooth phone connectivity, a dash-mounted MMI electronics controller with a 6.5-inch display screen and a 10-speaker sound system with a CD player, an SD card slot, iPod integration and satellite radio.

The Prestige package adds adaptive headlights, a 14-speaker Bang & Olufsen sound system and a Technology package, which includes a color driver information center, a rearview camera, rear parking sensors, a blind spot monitoring system, a navigation system, an upgraded version of MMI with controls mounted on the center console, a 7-inch display screen, voice controls, Bluetooth audio connectivity and Audi Connect telematics with mobile WiFi hotspot capability, Google Earth map data and Google Voice local search.

The upgraded stereo and the Technology package are offered as stand-alone options on the Premium Plus. Available exclusively on Prestige-equipped S4s is the Driver Assist package, which adds adaptive cruise control and adaptive steering.

Optional on both Premium Plus and Prestige are a High Gloss Black package (19-inch dark gray wheels, gloss-black exterior trim and mirror housings in body-color paint instead of the standard silver), a torque-vectoring sport rear differential, adaptive dampers (with adjustable settings via drive select), premium leather upholstery and rear side airbags.

The special-edition Nogaro Blue package includes eponymous paint, unique 19-inch wheels, aluminum inlays from the Euro-model RS 4 and sport seats with blue simulated-suede inserts.

The 2015 Audi S4 is motivated by a supercharged 3.0-liter V6 engine rated at 333 horsepower and 325 pound-feet of torque. All-wheel drive and a six-speed manual transmission come standard, while a seven-speed automated manual (S tronic) is the self-shifting option. The available sport differential can distribute torque between the rear wheels in a matter of milliseconds to improve the car's cornering line.

In Edmunds performance testing, a manual-equipped S4 accelerated from zero to 60 mph in a swift 4.9 seconds. An S4 with the automated manual bested that time with an even quicker 4.5-second run.

EPA-estimated fuel economy for the S4 is 20 mpg combined (17 city/26 highway) with the manual and 21 mpg combined (18/28) with S tronic. That's fairly frugal for a high-powered, supercharged V6.

The 2015 Audi S4 comes standard with antilock brakes, traction and stability control, hill start assist, front seat side airbags and full-length side curtain airbags. Rear seat side airbags are optional. The Technology package adds a rearview camera, rear parking sensors and a blind spot monitoring system. Prestige models include the Technology package and are eligible for the Driver Assist package, which includes adaptive cruise control with full-stop capability and a forward collision mitigation system that provides full automatic braking under 19 mph.

In Edmunds brake testing, the S4 stopped from 60 mph in 109 feet, an average distance for this class of sedan with summer tires.

In government crash testing, the S4 came up aces with an overall rating of five out of five stars, including five stars for frontal impacts and five stars for side impacts. The Insurance Institute for Highway Safety gave the S4's sibling, the A4, its highest rating of "Good" in the moderate-overlap frontal-offset, side-impact and roof-strength tests, but the Audi earned the lowest rating of "Poor" in the small-overlap frontal-offset test. The A4's seat/head restraint design was rated "Good" for whiplash protection in rear impacts.

Audi's widely available supercharged V6 engine puts its best foot forward in the relatively compact S4 (and similar S5), generating relentless acceleration. Refinement is superb, as the 3.0T V6 transmits virtually no vibration to the cabin, even at redline. The manual transmission has somewhat long shifter throws, but is generally precise and rewarding, while the astoundingly quick and smooth S tronic transmission is equally pleased to shift for itself in full auto mode or obey your commands via lever inputs or the steering-wheel-mounted shift paddles.

In spirited driving, the S4's brakes inspire confidence, yet they're never grabby. Handling is nimble and precise, and it's enhanced noticeably at the limit by the optional sport differential, which minimizes the understeer to which the nose-heavy, front-drive-based S4 is naturally prone. Thankfully, ride quality remains quite comfortable, and the cabin is appropriately hushed at speed. The S4 may not be a max-attack machine like the BMW M3, but its sophisticated performance makes it an intriguing alternative to a variety of sporting sedans.

Audi's enviable brand image is due in part to its stylish, sumptuously trimmed cabins, and the S4's innards certainly don't disappoint. Materials quality is generally excellent, and the understated dashboard design with its tasteful metallic accents will look just as classy a decade from now as it does today. Compared to the A4, the S4 adds form-fitting sport seats, a flat-bottom steering wheel and gray-faced instruments, subtly signaling its sporting intentions without making a fuss about it. Some basic functions can be a pain to actuate, however; the climate control system, for example, requires multiple steps simply to adjust the fan speed.

Infotainment features are controlled via Audi's MMI, which consists of a controller knob and related buttons that control menus on a central screen. Overall, it's an effective system, though we've found BMW's iDrive and Mercedes' COMAND systems a bit more intuitive to use. Notably, in S4s without the Technology package, the MMI knob is located on the dashboard, potentially requiring an unwelcome reach from the driver seat to make adjustments. But when that package is present -- as it is in most S4s -- the knob and buttons migrate to the center console between the seats, where they fall readily to hand and control an upgraded 7-inch display.

Interior versatility is an S4 strength. Drivers of all sizes should have no difficulty getting comfortable behind the wheel, while four adults can ride comfortably on long trips. That's not a given for sedans in this size class. Trunk capacity is average at 12.4 cubic feet, but the rear seatbacks fold flat, opening up a claimed 34 cubes behind the first row.