Mikal, yeah the benefit of adding an external amp is more headroom with your speakers. I do go back and forth with Large and small, I noticed with just two channel listening its best to set the the towers to Large and no sub on as I find it more neutral with the music. However for gaming and movies, small is best for those subsonic levels of bass that your towers cant do. There are some Pros that like there towers set to large and some say small is the best way. I say which ever sounds best to your ears is what you should go with.