Sorry if I got a little technical before -- was trying to help him out. I think the largest issue with audio in general is that there are so many stereotypes, misinformation, and "general rules of thumb" that go around the net.
Such as the statement "generally one note wonders". I agree if we are talking about prefabs, they are horrible designs. However, if you are talking about a properly designed bandpass the range can be TREMENDOUS and far better than sealed or ported alignments. The last 3 blowthroughs I have done were designed to be completely musical, +-3dB from 35 - 60hz (my definition of musical). Two more of these coming up in an old big body chevy truck and an Avalanche on Friday.
Hell I probably really don't belong here, I don't own an FJ I just love car audio and popped my head in on a thread after backing up my buddy from hexibase forums.