2002 sport trac, stereo system

I have an 02 sport trac,the only possible way to get my 10in subs in is, there is an enclosed storage spce behind my rear seats,they barely fit but it would work. The only problem is that they wont be totally enclosed, what will this do to the sound? should I try to rig a way to totally enclose them? 

I see a  number of problems here. Subs are almost always desinged to be in an enclosure built to spec. Either sealed, ported, or a variance of the ported style.

Simply putting a sub in a storage unit is not going to produce any thing good, especially if the sub is hanging out. Another issue here is that more than likely that storage bin is made of plastic. How do you think a sub is going to sound in a flimsy plastic enclosure that doesn't entirely fit it??

Take heed to the above advice about proper enclosures. Either get a prefab. or a custom built one.