The new 5 is 2.6 inches longer, 1.8 inches wider and 1.3 inches taller than the 2003 model, and its wheelbase has increased 2.6 inches. Nonetheless, all that aluminum keeps a lid on the car's weight. Depending on equipment, some 2004 models are up to 55 pounds lighter than their predecessors. A new aluminum driveshaft saves 13 pounds compared to the previous steel part. The hood, front fenders and frame in front of the windshield pillars are also aluminum, glued and riveted to the rest of the car to avoid the corrosion typical of aluminum-steel contact points. The lighter front clip also helps in BMW's never-ending quest for perfect weight distribution, and all three 5 Series sedans come within one percent of the ideal 50/50 balance, front to rear.

What gets everyone's attention, of course, is the 5 Series' swoopy exterior design, and in this instance, attention may or may not be a good thing. The 5 adopts BMW's new brand-wide design theme, launched on the flagship 7 Series in 2002. At no time in recent memory has automobile styling generated such controversy. With the release of the 7, rogue members of the BMW Club of America launched a web site to generate momentum to fire BMW's design chief. The new 5 is definitely cast in the 7 Series mold, with a curvy front end, flat flanks with minimal embellishment and a high, flat rear deck with wraparound taillights. On the 5 Series the look seems a bit more cohesive, perhaps a less radical departure, but that may be because we've gotten used to the 7.

You'll like it or you won't. The critics claim that, with the flared-nostrils look in front and the chunked-off shape of the trunk lid, the 2004 5 Series seems almost like two halves taken from different cars. In our view, the lines make for a compact package, and that may be part of the problem. Some have suggested the new 5 has the appearance of a well-made mainstream Japanese sedan like the Honda Accord. While the Accord is an outstanding car in its own right, that isn't the precedent one expects for an expensive European job. And either way, despite the hailstorm of comment and criticism that followed the launch of the 7 Series, BMW's new look hasn't seemed to hurt its sales.

Those comma-shaped taillights use another of the 5's new technologies, something BMW calls adaptive brake lights. These illuminate more intensely, over a larger area, when the driver applies the brakes full-lock, or when the ABS operates. The idea is to inform drivers in cars following the 5 Series that it's stopping quickly. Interesting, we suppose, but it would seem to work only if the driver following the 5 knows how to interpret the varied intensity of its brake lights.