DD woofers mock up worse than most drivers.. but there is no doubting their capability in the output department..
subjectively... they are a bit limited in how good they can sound at high output levels.. their forte, if you can call it that.. is rock music, with quick, separate beats. Even then, they have a tendency to be overbeing..
you go and try to run demanding multi-frequency sustained notes through them.. they do a good job of mushing it together into a single undistinguishable line..
optimum enclosure for a DD, would be a moderately volumed ported enclosure, tuned extremely low, to mellow out the exaggerated peak above tuning... but then you're shooting yourself in the foot over the main reason to run DD woofers..
so pick your poison and go..
personally to me, the dub sebbin doesn't sound very good either.. so I'd go the DD route...
the truth about the car audio industry... is most people don't care about distortion v/s ouptut.... the wang always wins..
Loyd L.