[kk2002s]

Ok I'm in the the same thinking of adding an extinguisher.
But as you point out how would you spray the engine.
Right now without modifications, you might be able to spray through the right side vent but not sure how effective that would be.
Maybe add some plug/tube through the passenger firewall but then you have to be in the car
Through the trunk firewall, but then you have to be able to open the trunk

Maybe just stand back, get out the phone, record it and put up on you tube.
Don't forget to record your tears streaming down as your Boxster burns up