I have had many orders of Uco stormproof matches sent to me. In fact, I just received the new Titan stormproof matches. They are the same thing much larger. It says they will burn for 25 seconds. I will test them and let you guys know. They may have trouble fitting in some kits due to the size, but I think they will be good for the car and a backpack.
I always have at least 3 fire starting methods in each survival kit, along with 2 or 3 types of tinder. Doesn't take up much room, but increases your chances of success tremendously. Usually it is not the fire starting method that fails, it is the tinder.