I'm using 2 8"s in ~.5cuft total, and it blends pretty well (although SOMETIMES bassheavy for MY taste) in an xtracab truck. I tried it with 1 8" in .25cuft and it wasn't loud enough for me (but thatll be sub dependent too). So basically, I kept 2 because I'd rather have too much bass and tune it down, then have too little bass and have to boost it into distortion.
