What's the best 'sub' to go with this set? I want very good low bass.
And also I've always had floor tower speakers, 3 way with 10 or 12 inch woofers, can a 'sub' box and smaller speakers (8" in this case) really compete with a set of larger woofers in the tower?
With an independent sub, yes, it can most certainly compete. I paired this with a klipsch r12sw and it plays beautifully. Love the "punch".
For more boom, consider a 15' offering from klipsch for matching timbre. Beware the huge speakerbox.