Glad I'm not the only one that has thought about this. And yes I agree a Halon or Halotron or similar is the way to go. Just thinking out loud hear, so you realize you have a fire. You quickly pull over to the side of the road, set the parking brake and reach over to undo your passenger seat mounted extinguisher. As you exit the vehicle you release the rear trunk. You run around to the trunk, rip the carpet off the front trunk/firewall to expose the 1/2 " diameter hole you previously had drilled. Pull the pin on extinguisher, insert nozzle into the hole and fire away until empty. Crazy idea or plausible ? If I were to drill a hole not sure I would put any type of plug in the hole, that could either melt/burn your fingers or take valuable seconds to fumble with. If nothing else we have a good discussion going
Or do you go whole hog and install a racing system with nozzles hard mounted in the engine bay ? Maybe mount the extinguisher in the rear trunk then your lines to the nozzles only have to be 2 ' long or so .