What was tested? 2007 Mercedes-Benz E320 Bluetec

Options: Iridium silver paint ($700), panorama sunroof ($1,000), electronic trunk closer ($520), Premium II Package ($4,290).

Price as tested (including $775 destination charge): $58,835.

Mercedes-Benz makes some very nice cars, but I don't think that's the only reason people buy them.

No, people also buy a new Mercedes when they have something to prove. They know they were teased in the seventh grade for wearing the wrong brand of tube socks and having asymmetrical nostrils, so they drive a Benz to prove they don't deserve that Crooked Boogers nickname after all. It's a form of social validation.

When Fungus Foot Fred pulls up at his high school reunion in a big, shiny car with a three-pointed star on the hood, it says something -- something loud and assertive, but with a very polite tone of voice. It says, "I'm not who you thought I was."

So, if you agree with my theory on Mercedes sales psychology, it's only logical for M-B to produce a car that mirrors its buyers, one that's not at all what we'd expect based on what we saw in the past. That car — the one that would have gotten its lunch money stolen every day in middle school a few years ago — is the 2007 diesel-powered E-Class.

Called the E320 Bluetec, it's not like the diesels you remember from years past. It's amazingly stylish, quiet and refined, so much so that it's almost impossible to tell it's a diesel without looking at the label on the gas cap. The engine politely hums at idle, with hardly a hint of the belching, clap-clap-clap sound you'd expect from a diesel engine.

There's no better example of how automotive technology can change over time, much like Smelly Sally from your sixth-grade English class somehow turned into a Miss America finalist.

When I was a kid, I lived across the street from a man who drove a school bus every morning. Each day before sunrise he would wake up early and drive to the bus barn in his Volkswagen Jetta diesel, which wasn't merely loud enough to frighten the whole neighborhood. It was loud enough to wake up every living creature in the northern hemisphere.

It also seemed like his Jetta had to be warmed up for two days before it could drive, so it would sit for an eternity in the driveway, spewing smoke, smelling like a refinery and making enough noise to knock jumbo jets out of the sky. He would have been arrested if the cops' cars didn't fall apart upon reaching the lethal wall of diesel sound and sooty, stinky smoke.

That old diesel couldn't be more different from the new ones, even if it grew horns, wore a grass skirt and started dancing the hula. The Bluetec is freakishly quiet, like you'd expect a Mercedes to be, but it's also a mobile billboard for Greenpeace, something the dirty old diesels never could have been.

Thanks to tighter emissions regulations in the United States, the Mercedes E320 is the only passenger car available with a diesel engine in 2007. It uses a complicated exhaust system to clean up the engine's fumes before they exit the tailpipe, resulting in cleaner emissions than any other diesels to date.

It also gets gas mileage that will knock your name-brand socks off. This car, which makes 388 pound-feet of torque, gets an incredible 27 miles per gallon in town and 37 on the highway. That's better than anything else in the mid-size luxury class. Heck, it's better than most economy cars.

While the E320 has the soft leather, smooth ride and impressive gadgets you'd expect in a Benz, it also has a couple of downsides. For one, the navigation system was designed by drunk monkeys. It's so illogical and counterintuitive to use that you'd be better off with paper maps drawn by Lewis and Clark.

For another, if you look in the Guiness Book of World Records under "most boring car in the history of humanity," you'll find a picture of the E-Class. It's comfortable on the highway, sure enough, but it also feels like you're driving a casket. It provides no excitement, no satisfaction in corners and no driving fun, other than the guilty pleasure of knowing you're behind the wheel of a Benz and everyone else isn't.

A great thing about this car, though, is the price. The diesel-powered E320 costs $52,325, which may seem like a lot at first glance. But when you consider it's only $1,000 more than the gas-powered E350 that doesn't have the high-tech diesel engine, gets far worse gas mileage and has less torque, the Bluetec looks dirt cheap in comparison.

Pros: It's a diesel, but not at all like the ones you remember. It's shockingly quiet, has clean emissions and gets gas mileage that you simply won't believe. And, of course, the Mercedes badge is a nice plus.

Cons: It sets the worldwide benchmark for boring cars. Any vehicle this expensive should get you excited, not make you yawn.

RATINGS (1-10)
Style: 10
Performance: 9
Price: 7
Handling: 4
Ride: 10
Comfort: 10
Quality: 8
Overall: 9