The Dayton HO 10 is great for SQ too. I've had w6s, old and new... LOVE EM TO DEATH. The Dayton HO keeps up with it SQ-wise, though...sealed or ported.
Its worth a look into. In my experience, the w6 feels like itll take more power and its very easy to get loud and low with it even small sealed. The Dayton seems to need a little more juice to get going, but doesn't feel like it'll take what the w6 will. Almost like it has a sweet spot, that, once u find, you're in heaven. I love my Daytons as well. I was running 2 ported , tuned at 29hz on about 400rms each and they got plenty loud and sounded great up to about 70hz. I switched up to one sealed on about 400rms and it still sounds great and will get decently low (not as loud down low as ported or the w6), but the thing extends crazy high man and still sounds clean and is still hard to localize.
Both subs would be fine choices, IMO.
I hear about ID stuff all the time, maybe I'll try one someday....