The BMW 3 Series is often called the best sedan in the world. The Bavarian automaker today unveiled the sixth design of the 3 Series since 1973. The question is whether the company has done it again. Will it keep the crown?

The 3 Series is not only hailed globally, but it is by far the most important vehicle to BMW's current financial performance and future growth plans. It is built in four plants, including the Munich plant that is in the same neighborhood as the company's headquarters.

How does the all-new 3 Series compare with the old one? BMW has stretched the car's new shape around an engineering platform that's larger in every dimension. Its front track is wider by 1.46 inches, the rear by 1.85 inches and length has increased by a full 3.66 inches. Despite being bigger, the new 3 Series is also 88 pounds lighter than its predecessor. Those extra inches outside translate to a smidge more rear seat room inside. What BMW defines as "legroom inside the doors" increases by 0.71 inches and knee-room is up by 0.6 inches, while headroom grows a scant 0.31 inches. As mentioned, trunk space has grown with the 2012 model to swallow three golf bags at once.

The new 3 Series is also marked by the arrival of BMW's new turbocharged 2.0-liter four-cylinder engine that first debuted in the new Z4 roadster. This move to four-cylinder engines may take some Bimmer enthusiasts by surprise. But, in fact, BMW is going back to the future. BMW's four-cylinder engines were key to the company's rise in the 1960s and 70s as the premier maker of sports sedans. And while a four-cylinder engine is a novelty in a premium performance car in the U.S., BMW has, in fact, never stopped offering them in the 3 Series in Europe where gas prices are higher and fuel economy more of a priority. BMW is so identified with the four-cylinder engine in Europe that its headquarters in Munich is literally designed to look like four cylinders.

>>View Gallery: 2012 BMW 3 Series


The benefit of the four-cylinder over the six? More power for less dollars at the pump.

Replacing the brand's venerable 3.0-liter inline six-cylinder in the 328i model, the new four-cylinder produces 240 horsepower and 260 pound-feet of torque, both significant increases. BMW claims the new 328i will also be more fuel efficient despite the extra power, and while fuel economy numbers aren't available yet, the company does say the new 328i will scoot to 60 miles per hour in 5.7 seconds and on to an electronically limited top speed of 130 mph.

The more powerful 335i model retains its N55 single-turbo 3.0-liter inline six-cylinder that once again produces 300 hp and 300 lb-feet, but thanks to new fuel-saving measures like Auto Start-Stop, Brake Energy Regeneration, an ECO PRO mode and new eight-speed automatic transmission (a six-speed manual is standard), BMW says the 335i can now achieve an estimated 32.6 mpg, though, again, official EPA numbers aren't yet available.

The new 3 Series will be available in four trim levels to suit individual tastes: Sport Line, Luxury Line, Modern Line and M Sport Package. The Sport Line is identified by its dark side, which means lots of gloss black trim on the exterior, as well as gloss black interior bits with red accents. The Luxury Trim, in contrast, favors shiny chrome and receives a special set of 18-inch multi-spoke alloy wheels. The Modern Line is a bit more subtle, decked out in satin aluminum trim with 18-inch turbine-style alloy wheels. Lastly, the M Sport Package alters the sedan's new look with an aerodynamics package and 18- or 19-inch M Design wheels. While falling short of a full on M car, the M Sport Package does also offer an M Sport suspension, M short-shifter and various other M-branded bits.

3 Series Hybrid

Lastly, the 2012 3 Series gains some tech enhancements that include a new full-color, high-resolution Heads-Up Display; Active Blind Spot Detection System; Camera monitoring for a Lane Departure Warning System and Collision Warning; and a new Surround View system with Top View and Side View to augment the rear-view camera. The 3 Series lineup will also welcome a hybrid variant later on in 2012 called the ActiveHybrid 3 that produces a combined gas/electric power output of 335 hp and 330 lb-ft of torque.

The 2012 BMW 328i and 335i will arrive in U.S. showrooms in February 2012, with pricing to be announced at a later date, while the all-wheel-drive 328i and 335i xDrive models will be available in this summer. The ActiveHybrid 3, meanwhile, goes on sale in the fall of 2012. Now the only thing left to do is drive them. Stay tuned, and we will let you know if BMW keeps the crown when they give us the opportunity to air out the new cars on the autobahn.
with John Neff of Autoblog



AOL Autos Editor-in-Chief David Kiley is author of Driven: Inside BMW, The Most Admired Car Company in the World; John Wiley & Sons, 2004.