he can build it for single or dual sub's and it isnt going to take up much room in fact you will still be able to use the spare tire trap door on the floor thingy. dont use a ported box. all you'll do is rattle the crap out of your trunk and unless your going to port it up threw your rear deck its a waste of time/go with a sealed box and this is why i want you to call mike dirrect so he can make it to the right spects you need. he has all the air space charts for every woofer out there and will build you up some thing quick and to your needs. 90% of the time you'll have your box with in 4 or 5 days of calling him. and another thing is the charger is hard to get bass in threw to the interior of the car. well that depends on what your use to as far as bass-me i have to have it pounding so 1 woofer wont cut the mustard for me-if all you want is a little bass fill in-then 0ne L7 WILL BE GOOD. but if you want to scare the paint off of 94 honda's then you'll need 2
If you are having trouble getting the bass into the car, cut a port or two in your rear deck and either cover them with a speaker grill, or some type of mesh and recover the entire deck with a grill coth or something. Usually materials, if they are pourous (sp?) enough, won't bother bass.