Security consultant Tony Scotti watches as a black sedan squeals away from a stop and maneuvers through traffic cones set up as a slalom course. "Handling isn't compromised, and you've got those three extra seconds to get out of the kill zone," he observes. Scotti's talking about the new Mercedes-Benz S500 Guard, on the market this fall as the first armored passenger car the company has offered in the U.S. Mercedes expects to sell 100 or more annually to corporations, high-profile individuals, and government agencies here, primarily to thwart random street violence, smash-and-grab robberies, and car-jackings. Built on a dedicated assembly line, the car gets ballistic steel armor plating installed before the normal body skin, and composite glass nearly an inch thick is used in the windows. The passenger compartment can withstand direct hits from a .44-caliber magnum weapon, the basis for certification to the European "B4" protection standard. "It's a time machine," said program manager Rob Allan. "It buys those few extra seconds." Yet the car is intended for everyday use, with performance and handling characteristics similar to the standard S500. To the observer there is no apparent exterior dissimilarity—in other words, it doesn't look like an armored auto. To the user, noticeably heavier doors, front windows that roll down only two-thirds of the way, rear windows that don't roll down at all, and a slightly more weighted feel on the road (it's 802 pounds more) are the only clues that this isn't a normal car. The $153,950 base price (almost double that of a standard S500) includes run-flat tires and the usual Mercedes new-car warranty. Call 800-367-6372 for information.