BMW and Mercedes-Benz continue to be the front-runners in the luxury segment, but Audi has been gaining on them. What it may be missing in cachet, it makes up for with charm--demonstrated well with its smart, thoroughly competitive A4. But can the A4 actually outpace the newest 3-Series--with all its body styles and power choices? The A4 is the brand's bread-and-butter model. On the outside, it can seem understated where the BMW 3-Series is bold. Inside, the A4 is an entry-level tailored suit, perhaps a half-step behind what you can get in the latest 3-Series, if you pay quite a bit extra. But behind the wheel, the A4 is poised, and satisfyingly capable, landing somewhere between plush and focused. It's this balance that gives the A4 its charm, and it's that balance that makes it a serious rival to the 3-Series, even though BMW sells more cars.
Audi doesn't quite offer the wide range of powertrains that BMW does. Under the hood, the base A4 uses a 2.0-liter turbocharged engine--a move made well before BMW's addition of the 240-hp turbo four in the 328i model. With 220 horsepower, it's closely matched to the 3-Series, though it ultimately comes up short on the spec sheet. On the other hand, BMW's prices have risen sharply over the past several years, and the lower-output version of the 328i's engine, making just 180 hp in the 320i, is close match to the A4 2.0T.
Unlike the 3-Series, however, you won't find a potent six-cylinder in the mid-range; you have to jump all the way up to the S4, where you'll find a 333-horsepower supercharged V-6 engine, an aggressive suspension, and rakish styling that rivals the M3's--though again, the Audi comes up short on power numbers. The latest M3 generates 425 horsepower from a 3.0-liter twin-turbo six and dual-clutch gearbox (for a 0-60 mph time of as little as 3.9 seconds).
BMW also offers the 335i, with a turbocharged in-line six-cylinder good for 300 horsepower and 300 pound-feet of torque. There's also a 328d, with 181 horsepower from a turbodiesel four-cylinder engine.
Also unlike the 3-Series, the A4 is a front-drive-based sedan, with quattroall-wheel drive available in higher-trim models. While this bias--and its frontward weight bias--ultimately brings it up somewhat short of the 3-Series' ultimate dynamics, the available quattro system makes the A4 as competent as any luxury sedan in foul weather. BMW's xDrive system is available in the 3-Series, but only in a limited number of models.
Further distancing itself from the 3-Series, the Audi A4 is available as a wagon--or Allroad, as Audi styles it for the latest model year. BMW is reviving its 3-Series wagon but without the more overt styling cues, while it's split off its two-door models into the new 4-Series and M4 range.
Front seats are spacious and comfortable in both the 3-Series and the A4, though the latest 3-Series sedan grows an inch in wheelbase, dedicating most of that to rear seat space, where it is noticeably roomier than the A4's close quarters, particularly when it comes to leg room. Neither is spacious, however--a classic tradeoff in the segment.
Quality, fit, and finish are very good in both cars. BMW's cockpit has improved, though some touches can seem out of character--like the optional nav screen that perches on top of the dash, instead of integrating into it. The A4 is a more seamless piece, with a lush new LCD screen that renders Google Earth and Street View maps in gorgeous detail. For most, it will come down to a matter of taste: where the BMW is sometimes drab, sometimes busy, the Audi is sleek and polished, uncluttered and largely intuitive. Creaks, rattles, and other signs of poor build quality are non-existent in the A4.
When it comes to ride quality, both cars err a bit toward the sporty side, showing occasional harshness over rougher surfaces. Some will call it the price they pay for their sharper handling, but others will find the Mercedes-Benz C-Class's more plush ride preferable to either. BMW's steering tracks much more cleanly than the A4.
Both cars also offer a host of advanced technology, with iDrive powering the 3-Series' infotainment and MMI behind Audi's. While both systems are advanced and capable, MMI is slightly more intuitive to most. Both of these cars now have Bluetooth standard across the model line. The 3-Series also offers an excellent head-up display (HUD) that's just become available on the A4, tying speed, navigation, and other information into a display projected onto the windshield. Audi also has in-car wireless Internet with Audi Connect, which in turn feeds data to that exceptional nav system.
One bit of technology the A4--and S4--come with that we'd rather it didn't is Drive Select, as system that offers adjustable control of the steering, damping, and other characteristics of the car. It comes off as gimmicky, changing feel but not improving the car's communicative aspects or handling in any noticeable way.
Finally, the matter of safety. The BMW 3-Series is perhaps a step ahead; it's been rated five stars overall by the National Highway Traffic Safety Administration (NHTSA), while both models have mostly 'good' Insurance Institute for Highway Safety (IIHS) ratings. Neither one does particularly well in the IIHS small-overlap frontal test ('marginal' for the 3-Series and 'poor' for the A4).
With the wide range of models and body styles tucked under either nameplate, both the BMW 3-Series and Audi A4 have something to appeal to most luxury buyers. The BMW still has the performance edge that adrenaline junkies seek out consistently, though the Audi S-cars aren't far off. But when high-tech gadgets and a purer design are the better lure, it's the Audi lineup that wins.