I'll start by saying I don't dislike my sub, but enough reading will give any guy upgraditis. There are several out there which may fit the bill, but I am currently most attracted to the SVS PC-13 Ultra. I have read the DIY discussions, and I admire what you do but that's not the route I'm going to go. I've already read much of your input, so you don't have to re-post it here.
Anyway, I've been running this sub for about 4 yrs in my approx. 2550 cu ft LR, which opens to our entry hall, DR and wraps to the kitchen. My listening environment is not ideal, but it's what I've got. I believe my current speakers will keep up with an upgrade and don't expect you guys to research, but just to save a question, I'm running Accoustic Energy Aelite 3's
http://www.acoustic-energy.co.uk/Product_range/Aelite_series/index.asp in the front as well as the matching center console. I scored these on a closeout and the surrounds didn't come in a matching wood, so I picked up Boston VRM50's for the rears. I'm likely to go 7.1 in the near future. Due to room configuration and a large fish tank, I don't see a second sub as an option.
Kind of a long intro to get to my biggest concern--I'm on a raised foundation with wood floors. From the reviews of subs I've read in this class, they sound like they may give too much of what I crave and will be more distracting than complimentary. Is that wrong? I would also be open to putting the unit on a Subdude if that would help. I believe the Subdude is 15" across, while the PC-13 is 16" in diameter at the base - problem?