I have a single vibe black air 12 in the my boot and am in the process of building a thin custom box to push to the back of my boot to take up less space, also got my genisis p4ultra amp under a false floor. Im in desperate need of space for my clubs ect and once the sub box is in il have more than enough. It sounds amazing by the way!
Like you said, if you hav a puncture you are fecked! and youd have to cover the sub up in order to stop it gettin damaged every time you put something in it, which kinda defeats the object!