Vehicle Overview
Mercedes-Benz has updated its E-Class midsize sedan for 2007, adding two new optional engines, styling changes, a Pre-Safe system and an AMG performance variant. Pre-Safe is arguably the most advanced collision-mitigation system on the market, and Mercedes claims that its optional Bluetec diesel engine is the cleanest available.

The V-6-powered E350 continues, and a new 5.5-liter V-8 changes the E500's name to E550 for 2007. The diesel E320 CDI is now called the E320 Bluetec, to represent the engine's new emission-control technology. The new E63 AMG replaces the E55 AMG.

It takes more than a casual glance to recognize how styling has changed between the 2006 and 2007 models. Mercedes says the headlights have been redesigned, but we're not seeing it. The grille changes are subtle — an apparent blacking-out of the vertical bars and the addition of a Mercedes badge on the upper span, immediately in front of the star hood ornament. The rear end also is ostensibly restyled, but all we've been able to find is a wide chrome strip above the license plate.

Test your skill: Try and find a difference between the 2006 and 2007 E-Class, the Where's Waldo of the automotive world. More obvious is a deeper front bumper with larger grille openings.

Changes inside include a slightly different shift lever, a slightly different climate-control layout and a new steering wheel that does away with the rubbery touch-pad-style controls. Some previous options are standard for the first time: a moonroof, six-CD changer, Harman Kardon premium stereo and, in the wagon body style, a power liftgate.

Under the Hood
The E350's 3.5-liter V-6 funnels 261 horsepower through a seven-speed automatic transmission. The E550's V-8 increases power to 382 hp from 302 hp in the E500's 5.0-liter. The E65 AMG replaces the earlier version's 469-hp, supercharged 5.5-liter V-8 with a 503-hp, normally aspirated (not supercharged) 6.3-liter V-8. Finally, the E320 CDI is now the E320 Bluetec. Mercedes says the Bluetec system is clean enough to be the first diesel car engine of modern times that can be sold in California and other states with stringent pollution restrictions. It achieves this by decreasing diesel's two worst pollutants: particulates (soot) and oxides of nitrogen. A special catalytic converter, a particulate trap and another device in the exhaust stream filter or convert the bad stuff into benign gases like nitrogen.

Unfortunately, none of this will work with existing diesel fuel in the U.S. Low-sulfur "clean diesel" fuel, which will begin to roll out later this year, is the secret to making this a success. Put all these elements together and you'll get unprecedented clean exhaust and 35 mpg in combined city/highway driving, according to Mercedes.

Previously available only on the S-Class, the Pre-Safe collision mitigation system joins a generous list of standard safety features. There are dual-stage airbags in the front, side-impact bags in the front and rear doors and side curtain-type airbags that cover the side windows. Antilock brakes, brake assist, an electronic stability system and radar-based adaptive cruise control are onboard, all of which play a part in the integrated safety system.

If the radar sensor predicts an impending collision, Pre-Safe cinches the front seat belt pretensioners and can even change the position of the front passenger seat for optimal protection by the restraints. In a serious skid, the system closes the moonroof and any open windows, a step to prevent occupant ejection, which can occur in a collision or, especially, a rollover.

The 2007 E-Class will include an adaptive brake light, which flashes when the car is under rapid or panic braking. A flashing light is found to attract a following driver's attention faster — enough to shave a car's length of stopping distance by a car following at 50 mph.

If all else fails and the E-Class does crash, the standard Tele-Aid — which is similar to GM's OnStar — will contact authorities and send them to your location.