Trunk of your car is a BAD idea! Illegal in many areas due to fact in a collision it will rupture and burn like crazy or explode. No steel panel behind rear seat as would be required if a tank back there.
Storage near flame sources can be dicey. Any fume leak (common) and KABOOM!
Actually, running the carb dry when using StaBil is not real good idea. Here's why: When gaskets, needle valves and the like are new, they contain a "plasticiser" to keep them pliable. When exposed to gasoline, the plasticisers are "leached" out and replaced by gasoline. As long as the gas is there, they are OK for years. Let them dry out and they get hard and shrink. Result CAN be leaking and/or non functioning carb.
Interesting about gas going bad. Most of the problem is caused by bacteria that live in the water in bottom of container and "eat" gasoline! Their waste products we know as "varnish". Evaporation and slow migration throught plastic containers can also rob gas of the lighter, more volatile components of the brew making engines hard to start. Tightly sealed, clean and with a good stabilizer the stuff can last for years. Best to rotate SHTF stocks annually, however.