custom sub box

hi, the sub im thinking of getting has needs a 1.5cu feet sealed enclosure or 2 cu feet ported. to make a rectangular box this big to fit where i want it will be just about impossible cause i have the targa roof that clips into the boot which give me about 10" on an angle between the backseat and where the targa will sit. the sub is just over 8" deep so im going to have bugger all room between the ass end of the sub and the bottom of the enclosure. the enclosure will also have to be fairly long to allow for how thin its going to be. how will this effect the sound is it okay to have a mong enclosure or will it stuff sh*t up?

thanks

its not good to have LIKE no airspace behind the woofer is what i have ONLY heard. i asked around because i used to be into custom box making and made some tight fit boxes and where ever i went on the net and asked around they said the reccomended around 2-3 inches behind the magnet