I have a set of pioneer 3.5" in the front, and a set of pioneer 4x10's in the back running of of a jvc cd/mp3 deck at 4x50w or something. I also have a Rockford Fosgate 10" sub running off of a 200w orion cobalt amp in the trunk.
I've had bigger and louder systems in other cars I've owned before and I'm pretty happy with the sound out of this. I mean, it's not gonna win any competitions but it does what I want it too. As far as bazooka tubes not producing anything under 20hz... that doesn't really matter, the human ear can't hear that low anyways... you'll feel it though. The bazooka tubes are kinda cheesy though, from what I have experienced. The box with my 10 in it is pretty small and takes up very little trunk space, and the way it's installed it takes about 30 seconds to remove.
Ryan