You and I are in the same situation. We have the same Axiom setup and basically the same size room. I've been wavering between SVS, HSU and also the new Outlaw sub, which was made with HSU. I am currently leaning towards the HSU STF-3. I've been told the STF-2 would work, but I really don't want to deal with the "what-ifs".

My wife shot down the SVS cylinder subs.

Good Luck