Not much- you arent going to fit much under most seats.
Ive seen single tens, 6 1/4's, 12's, enven a couple 15's under an old school K5 blazer bench seat.
But you aren't going to win. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif You need a big space to make big bass, as a general rule.