Why would you add 185 kg to a M5 ?!?

For an armoured car, an additional 185 kg is not that much. This M5 will only protect against handguns. Armoured cars that stop bombs and machine gun rounds will weigh 1100-1500 kg more. They top the scales at 3400-4000 kg.

As for the performance of this M5, generally, the acceleration of even the most heavily armoured car is not affected because of various gearbox modifications. The top speed will be reduced because of the tires. The acceleration of the factory-armoured BMW 760 Li and Audi A8 are said to be the same as the non-armoured versions.

Damn, I hate making the last post in a thread.

For amoured cars with B4 protection class the top speed is limited to 240 km/h and for B6/B7 armoured cars the top speed is limited to 210 km/h! But I can't really believe, that the accelaration is the same...?!

I don't completely believe the acceleration either, ree. The extra weight is so significant and I think engine modifications are needed to produce the same acceleration figures. However, most of the manufacturers of the B6/B7 cars claim acceleration is not affected. But then, they also claim that a B6/B7 car is built to the highest protection level, even though the glass is merely B6.

The only factory-armoured vehicle built to full B7/B7 armouring is the Mercedes-Benz Guard G500.

The M5 uses a SMG III and I doubt you can squizze more juice since it's already ruthlesly optimised vs. manuals and automatics. Big heavy cars need plenty torque, while fancy sequentials hate it.