I am trying to decide what subwoofer in the $200-250 range would work best for my 5.1 system and am looking for suggestions. My room is 22x13x8 and I will use it mostly for movies. My speakers are Polk RTi8 and I don't need it to shake the walls, just be sufficient for the room. Also, it needs to be 16" x 16" square or smaller. One of my options is the Polk PSW110 but would like suggestions for other brands. Is 100w RMS enough for the room? Does the speaker size matter much? I am a newbie. Thanks in advance.