To really appreciate the major changes in Mercedes-Benz's 2007 E-Class, you'll have to look beneath the surface.

Of course, there are cosmetic changes as well: new taillights, a chrome bar across the rear of the car, a different gearshift lever and steering wheel. But the instant you turn the key in the ignition, you know this is not the old E-Class.

	mbusa.com The Mercedes E550 features a 5.5-liter V-8 engine with 382 horsepower. It rates 15 mpg in the city and 22 on the highway. Click photo for larger image.

I tested the E550, the upscale model with an all new 5.5 liter V-8 engine that puts out 382 horsepower, rated at 15 mpg in the city and 22 on the highway. We're talking 0 to 60 in 5.4 blurry seconds.

It renders the ultrahigh-performance E63 AMG model almost superfluous -- unless you must have the fastest, best Mercedes E Class. Otherwise, I can almost guarantee the E550 will be more than adequate.

Pick-up from the engine is both smooth and instantaneous. Not a hitch, not a hiccup, not a flinch, thanks to the flawless shift work of the seven-speed automatic. The linkage on the gearshift lever is among the best around, with a solid feel as you run through the gears. With a nice, muffled rumble from the engine, you're gone.

All that power is matched with awesome stopping power. The E550 comes with Brake Assist, which measures the speed at which the driver hits the brake pedal and sends power to the brakes to reduce the stopping distance. It compensates for the many times that drivers fail to hit the brakes hard enough or fast enough in an emergency.

The only thing that detracts from the overall bravura performance was the steering system. It's too soft and over-assisted for the kind of performance driving that this car is capable of.

I also had problems with the complexity and design of the navigation system and audio system. It really takes awhile to figure out how everything works, even with an owner's manual.

The entire 2007 E Class series starts at $50,550 for an E350, which is no slouch itself.

Base price for our test car was $61,500. With various packages and trims, the final tab came to $70,945. Standard equipment is extensive for the E550. It includes power accessories, electrically heated rear window with automatic shutoff, halogen head lamps and 10-way power seats. Other standard features include polished burl walnut wood trim, four-zone climate control and Harman/Kardon 12-speaker audio system.

The safety equipment includes side curtain air bags and the PreSafe system, which prepares occupants for a possible collision by tensing the seat belts, closing the sunroof and adjusting the front passenger seat to increase effectiveness of the air bag and seat belts.

This year, you can get your choice of either Sport or Luxury packages, both at no extra cost. They have different grilles and trim, and in the sport model's case, a lowered sport suspension, cross-drilled front disc brakes and a dual exhaust system.

Consumers on Internet car sites loved the E-Class' powerful engine and smooth transmission, handling, gas mileage, comfort and appearance. But they want improvements to the rearview camera system and better initial quality, particularly with the electronics.