Thank you everyone for the great comments. As an additional note, my room is not closed in, in fact it is a bit more than half of my basement where I have my listening area. The overall room is still 17feet wide but it's 18 feet in depth as opposed to 12 if you count in the 8 feet extra. This does not add significant cubic area so the advice offered still stands I just wanted to point it out. Although my first instinct is of course "get the bigger one" because then I cannot possibly have ANY reasons to upgrade my sub after that
I to was a bit concerned about placement of a sub that size. I would probably be just as happy with one 500 or two for flexibility and balance. After all, I have been running my system with my existing 10" 110W Energy sub for over 10 years now and it has served me well but I feel I am being shortchanged somewhat in that department. It performs well, but it works to hard in my opinion. With the EP500 or 600, it should not have to work very hard to fill my insatiable need for BASS .

Thanks again everyone !
Steph


Acoustic Zen Adagio, Veritas center, Axiom EP500, QS8s, Anthem AVM20, MC20,Adcom GFA7400