My 2 cents on fire extinguishers.
Do not go cheap! As a Fireman, I have seen many a nice car ruined by the use of dry chemical extinguishers. It looks like you threw a 5 pound bag of corn meal over everything, major mess that is next to impossible to totally remove.
I recommend a Halotron extinguisher. It is a gas that totally dissipates and leaves no residue.
One other thing, don’t drive with the deck lid locked. If you have to get in there in a hurry to put out a fire or whatever, you’ll be glad it was unlocked!