Last year, BMW redesigned the sixth-generation 5 Series luxury sedan, giving the exterior a smoother, more refined look than its predecessor, while taking on some of the styling cues and proportions of the larger 7 Series. Most noticeable is the cabin, which has moved back, creating a longer hood, shorter trunk, and a more coupe-like profile.

The new look discards the oft-criticized ungainly derriere of the previous model, which, to many, seemed disconnected from the rest of the vehicle. The twin-kidney grille has been lowered with a slight forward angle. The eyebrows remain, but appear less aggressive. While the look won’t leave anyone breathless and no one will chase you down to snap a picture, overall, we think it a pretty nice, if conservative, effort.

While BMW now builds the 5 Series on the much larger 7 Series platform with a 3-inch longer wheelbase, it’s just 2 inches longer in overall length. Unfortunately, this only results in a three percent increase in overall passenger room .

Otherwise, the interior is close to perfect, with the standard being Audi, whose efforts remain superior. Similar to the 7 Series, the instrument panel uses BMW’s “Black Panel” technology. Climate control and other readouts, such as warning lights, appear on the dark screen when necessary, and only four key gauges remain continually lit.

Occupants are cosseted in exceptionally comfortable seats that are upholstered in beige leatherette (BMW-speak for vinyl). As is the case with most everything on a BMW, real leather is an option ($1,450). Standard, however, has impeccable fit and finish with real wood and aluminum trim.

Over the years, one of the most maligned transgressions from any auto manufacturer has been BMW’s iDrive, an overly sophisticated glut of vehicle controls that resulted in more than the occasional utterance of four-letter words. And, for years BMW defended the dreaded iDrive system, insisting that the operation had a quick learning curve and owners would soon praise its capabilities with frequent use.

Thankfully the brass at BMW relented and repetitive-use operations are now more intuitive. It’s no longer necessary to page through a maze of complicated screen displays, utilizing a console-mounted mouse to adjust things such as the climate control or stereo. In fact, while it’s still present and simplified, drivers can entirely avoid using iDrive.

But any vehicle that brands itself as the “Ultimate Driving Machine” better get the drive right. For 2012, I can easily plead the case that the 5 Series remains true to its slogan. Some will say the ride feels a bit softer and handling not as crisp, but we think the optional Sport mode eliminates any sense that ride engineering isn’t as precise as expected.

The big news for the 2012 5 Series is a new turbocharged 2.0-liter, 240-horsepower 4-cylinder engine that replaces the incumbent inline 6-cylinder. The previous engine produced identical horsepower but with 30 fewer foot-pounds of torque. Enthusiasts will no doubt loathe the blasphemy that an Autobahn cruiser is possible with a 4-cylinder engine, as opposed to the time-honored 6- or 8-cylinder powerhouses. But the new engine is proof that not even BMW is immune to the sensitivities of outrageous gasoline prices and progressively burdensome Corporate Average Fuel Economy (CAFÉ) standards.

We tested a 5 Series powered by the new engine bolted to an eight-speed automatic transmission. To be sure, this is a small engine pushing around a fairly large luxury sedan, yet we found it amazingly quick with plenty of punch at any rpm.

The new 4-cylinder also comes with a mild-hybrid start/stop technology, which turns off the engine when the vehicle is stopped and the driver’s foot is on the brake. The engine starts again automatically with either the release of the brake pedal or turn of the steering wheel. There’s a button immediately below the push-button start that allows you to either turn this feature on or off. We left it on for almost the entire weeklong testing and can report that the system’s restarting execution was nothing short of startling, both noisy and jarring. The EPA estimates the fuel economy at 23 city/34 highway mpg, and unfortunately, the engine requires premium gasoline.

Standard safety features include four-wheel-disc antilock brakes, an electronic stability system with traction control, active front head restraints, and six airbags, including side curtains. There’s a host of optional safety features, most bundled in pricey packages such as the driver assistance package ($1,395), which includes blind spot detection, a lane departure warning system, and automatic high beams. Stand-alone safety options include park distance control ($750), rear-view camera ($400), night vision with pedestrian detection ($2,600) and side and top view cameras ($800). It’s also available in all-wheel drive and four-wheel steering.

What we didn’t like was the small outside rearview mirrors (sans a blind spot warning system) that severely restrict vision.

In crash and rollover tests from the National Highway Transportation Safety Administration, the 5 Series earned the highest possible five star rating. It also earned the Top Safety Pick designation for 2012 from the Insurance Institute for Highway Safety.

Overall the new 5 Series is bigger, better looking, and gets an ever-so-slight increase in gas mileage thanks to the new turbocharged 2.0-liter engine. But the vehicle seems to have moved from its sporty heritage to one that favors luxury. Perhaps the underpinnings of the 7 Series make the difference. And when compared to others in the class, it seems to have fallen slightly behind vehicles such as the Audi A6 and new Lexus GS sedans.