I replaced two cheap 10" with two 10" Jensen subs DVC at 4 ohms/coil (model sx1010). My problem is that the two cheap ones seemed to hit a little harder than the Jensens did. Do I need a bigger amp or do I need a different box, and if I do, what kind of dimensions do I need to max out my subs; sealed, ported, and bandpass(450 watts max/sub). Some dimensions would be a great help!!! I know a bigger amp would push them more, but if the cheap ones hit harder to begin with, I'd be better off putting the cheap ones back in with a bigger amp, but don't really want to.