I wanted to thank you all again for your help and thought I would follow up. I built a 2x2x2 ported box with a Dayton 18" HO driver. Safe to say that I am absolutely thrilled with the results. Decaf White Clouds makes the whole upstairs floor feel like a foot massager! My understanding is that this guy should be performing roughly like the PB13 Ultra for comparison sake. (Maybe better?

but i'm biased) I have
well under half of the PB13 invested obviously.
I'm 6ft and this thing makes me look small:
She is not painted yet but for now I'm just enjoying the bass: