AQ power is just as clean as Sundown amps, for example. Sure AQ and Sundown is dirty power if compared to Arc Audio's SE line. You pay for what you get. AQ is made, assembled and tested in house, in Korea. The more expensive amps might have parts made overseas, but some are either assembled/tested in USA before they go out. There is a lot of costs involved when you consider USA labor and AQ is a great budget amp, period.
OP I would highly advise you to make a new box. Wood isn't expensive. The rule of quality car audio is 70% install. The box makes a huge difference. The sub I recommended gets real loud and low for an 8. You could power 2 8's with 1200w rms.
That hexibase dude, Peter Kalluchi (SP), has his own channel on youtube. He has this silly show where he has people that don't know what he is running guess. I know a mic wont pick up what it actually sounds like, but you can tell it gets down and low for such a small single woofer.