A formidable A4

Dear BMW: Watch your back.

You've seen Audi launch a host of new models, some filling niches only centimeters deep. (The S5 coupe and Q5 crossover, we're talking about you.) You've seen them blowing marketing dollars on that weird Super Bowl commercial.

Yet you might have overlooked something: Audi's updated A4, the company's baseline sedan, wagon and convertible, which went on sale last month. The company spent $1 billion developing the A4's new, sturdier platform, and the car is good. It's even good enough to lure away some once-loyal BMW 3 Series customers.

Part of this had to do with money. The all-wheel-drive A4 with the turbocharged 4-cylinder engine starts at just below $33,000, and the 3.2-liter six-cylinder about $40,000.

Comparably equipped BMW 3 Series sedans with all-wheel-drive cost several thousand more, $35,300 for the 328i xDrive and $42,000 for the 335i xDrive. Another competitor, the Mercedes-Benz C300 4Matic, has an MSRP of $36,525.

Putting aside the measure of price, though, the A4 suddenly looks more attractive because almost everything on the 2009 model is improved over the previous version.

The A4 has always been a meat-and-potatoes kind of sedan — it'll get you where you're going efficiently and without a lot of speed or flash. Fair enough. If you're looking for added excitement, there was always the S4 model or even the more outrageous RS4.

Out on the road, as soon as I encounter a tank-sized Ford F-350 pickup veering erratically in the lane next to me, I feel the difference. I downshift the six-speed automatic transmission using the small behind-the-wheel paddle shifters and sweep by him, clearing the area before he swings heedlessly into my lane.

More assured

It's not that I would mistake the A4 for a sports car, but it's more assured and maneuverable than before. Easy and mild-mannered in traffic, it transforms into a slick and smooth machine when you need it to. Meat and potatoes with a kick of cayenne in the recipe.

Much of this newfound confidence comes from improvements you may not actually see — new proportions and better body rigidity. Audi used a lot of lightweight steel, which translates to greater safety and better handling. The sedan is also longer and wider than its predecessor and competitors, gaining 4.6 and 2.3 inches, respectively. Those new proportions also include a shortened front overhang and a wheelbase that's been stretched 6 inches. These changes give a better ride.

Not too radical

Nor did Audi get too radical in the exterior redesign. Most A4 buyers aren't looking for a "stare at me" automobile. The most obvious change in the new model is the revamped front, with a wider and lower grill, and halogen or LED running lights inside the headlights. Just like the R8 sports car, the lights form a swooping shape, and the effect is akin to a glare. Love it or hate it, they add personality.

Powerful four-cylinder

Both engine choices are direct-injected, and Audi says that even with the added power from that technology, they use 10 percent less fuel than the previous model.

I only got the chance to test the bigger engine, which is dynamic yet not particularly fast or impressive off the line. Its 243 pound-feet of torque is available at 3,000 rpm, and it takes ample time to get the engine up there. (BMW's twin-turbo six-cylinder, with 300 pound-feet at 1,400 rpm, is a breakaway winner.)

Many consumers may prefer the turbocharged four-cylinder, which is not only lighter but has 258 pound-feet of torque between 1,500 and 4,200 rpm.

Either way, prospective buyers should test drive both engine types.

Inside the car there's additional room, especially for rear passengers, who now have more space than their C-Class or 3 Series backseat buddies. The A4 will seat five in a pinch, and also gets a much bigger trunk, with about 17 cubic feet.

Up front, the A4 feels like an A8 luxury sedan writ small. Leather and heated seats are standard in most configurations, as is the Multi-Media Interface system, which controls most of the electronic gadgetry and is easier to use than BMW's still annoying iDrive.

If you want to go hog wild, you can also add assorted gizmos such as side assist (it lets you know if another car is in a blind spot), iPod integration, Bluetooth and a Bang & Olufsen stereo system.

What is most appealing in the end, though, is that the A4 is still content to fly under the radar. It's less about perceived prestige or extroverted design than simply serving as a comfortable and surefooted daily driver. It just handles a lot better than before.