Mercedes' 'Terrorist-Proof' Limo?

DaimlerChrysler's Mercedes unit says it has designed its new Mercedes-Benz S 600 Guard Pullman limo to offer "the highest possible degree of protection against terrorist attacks."

So what does that mean?

Here is how Mercedes describes its ultra-secure limo:

The highest protection specified for this car is equivalent to resistance level B6/B7, as tested and certified by state-approved organizations. Plus it meets further requirements that are not even stipulated by any standard, as tested by public and independent organizations. Its armor resists military-standard small-arms projectiles and provides protection against fragments from hand grenades and other explosive devices. Additional safety features include run-flat tyres, a self-sealing fuel tank and a fire-extinguishing system.

Mercedes says it will not deliver the Pullman Limousine, with a twelve-cylinder biturbo engine with 517 horsepower, until 2008. Why such a long lag time? Does it have something to do with the schedules of government budget protocols?

I also wonder who orders these types of limos. Is such security protection offered for U.S. senators or even state government officials in the United States? And how secure can a limousine be, anyway?