Because of a good friend of mine having his E28 533i burn and knowing of several other engine fires, I am installing a fire suppression system. Here is a picture of it. It is a 2.5 Liter bottle that when activated delivers a expanding foam (AFFF) that eventually breaks down into a water soluble liquid. The foam can fill the engine compartment over 10 times so there is not a chance of fire living in there.
Here is some info on the AFFF - Aqueous Film-Forming Foams are based on combinations of fluoro-chemical surfactants, hydrocarbon surfactants, and solvents. These agents require a very low energy input to produce a high quality foam. Consequently, they can be applied through a wide variety of foam delivery systems. This versatility makes AFFF an obvious choice for airports, refineries, manufacturing plants, municipal fire departments, and any other operation involving the transportation, processing, or handling of flammable liquids.
6% AFFF Foam is a proven effective concentrated liquid designed to form a dense foam to extinguish class A or B fires and alcohol fires. This material will smother fires and prevent air from reaching the flammable materials and lower the heat of combustion by cooling action.

AFFF provides foam and penetrating action to smother and cool all class A fires.

On class B fires provides smothering action from the dense foam plus the ability to form an emulsion with oils and other hydrocarbons, creating a cool barrier interface that lowers the temperature of the oils and reduces the heat of combustion of flashing action of the material.

Cleanup requires flushing with water.

AFFF is environmentally safe.

Here it is mounted in the engine compartment - not much to see.

I mounted the tank on the left side under the rear seat. The left side is deeper than the right and allows for the tank to be mounted without interfering with the seat once it is reinstalled.
The delivery tube was run with the wiring along the right side of the car. Plenty of protection is engineered into the channel that the wiring runs that will keep the tube from being crushed or kinked. All but 2" of the tubing was used, its a tight fit. Be careful how you use it. I cut the tubing with standard wire cutters and used a round punch to flair the end back out for the press on fittings to include the T and nozzles. Use grommets for all of the areas the tube passes through metal.

I mounted the nozzles in the fire wall shield. Once two holes were drilled, it was an easy fit. Tubing was a push to fit....way easy. .

The pull handle is mounted within reach while driving.

This system was $314 DEVILERED, you can not beat that price. Here is the web site of the Stable Energies where I bought the system - http://www.stable-energies.com/prodinfo.asp?number=SPA-LWM50
Mine is the SPA 2.25 Litre AFFF Alloy Mechanical Car Fire Extinguisher
That about does it. I just gotta keep my 6 year old and passengers from the "what does this red handle do?"