If I were you, I would do a small ported box tunned really low (28-30hz). I was on the same boat you were on to begin with about wanting to go sealed. I actually did do an SI Mag sealed and it was nice, but I wanted a little more output.
My philosophy was to build a ported box (that Immacomputer designed) that was slightly smaller than the measurements recommended for my subs (ported) and tuned it to 30hz. I absolutely love it! It hits quick and gets real low. Works great for all types of music. It's exactly what I wanted: the accuracy and cleanliness of a sealed box, but with the output of a ported.