Tony, you really can't have "too big".... the VP180 simply would produce your desired volume without any strain. Of course, the VP150 might not be straining at all, either (depending upon your desired volume level), but quite frankly, the reviews for the VP180 have been so substantial, I'd say go for it if you have the physical room for it!

::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::