RE: Fire Extinguishers
I'm not an expert and there probably are are others on this list that are.
But my understanding is that the problem (not counting the mess) with the
powder type units is that they pack down over time.  IIRC, where such
extinguishers are used in commercial buildings or shops there is a
requirement that they be picked up and shaken periodically or some such
routine.  I've always figured the riding around in a vehicle would probably
settle and compact the powder.  And I do recall someone on one of the VW
list reporting a very disappointing result when they tried to use their
original extinguisher.   I replaced mine with a Halon unit that fits in the
same area plus I have a small hand sized unit that I keep sitting on the
sink for instant access in case of a fire on the stove.  Halon is still
available but expensive as hell, just check your local phone book for a
place near you that sells such things.