Hey, I too was recently in a similar situation. I previously had 2 500w MTX towers that each had a 12" woofer. I presently have the 4Ts, 5C, 4Bs, & a crappy Sony 10" sub (for now). I was worried about the loss of bass & to my surprise there isn't much of one.

An old friend used to have CV towers similar to yours & those just like my MTXs had alot of bass, but the quality of the Aperion speakers makes the slightly less bass sound ALOT better than either set of towers. But I think the 8D addition will offer even more than the towers + the Aperion quality so I would definitely consider getting an 8D e if it's in your budget/if you have room for it.

If you could give us the listening area measurements better advice on which size speakers can be given.

(Point of reference: My room is 10'x12' )