I'm looking to add a sub (pair of subs?) to my existing set up, for about 250/300sheets, TOPS! My room is about 13ft by 15ft, and my existing setup consists of Mission M74 floorstanders, Mission 77DS surrounds, Marantz SR4200 Av/Rx, Marantz 4100OSE dvd/cd, (centre speaker also to be added). Is a pair overkill for a room of such small dimensions? Are Yamaha subs any use? They get good what hi-fi reviews, but average/poor home cinema choice reviews. All opinions/advice appreciated.