Dude, my room is bigger than yours and the 500 is awesome. I know lots of people with rooms your size and smaller that love the 500 as well. However, in reality, a smaller sub would most likely work also. I would hate to see you get upgradeitis, like I did from my 350, which I also loved.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85