Well, you'll really love the sound of your 30's and C7 once you add a sub. I really wanted an SVS, but was unwilling to wait 3 months for a sub. I'm a spontaneous shopper! I went with a DefTech PF15TL+, best sub I auditioned for under $1200, I paid $625.
It mixes well with my 30's,C7,S5's though I do have a slight itch for more bass after reading the overwhelming posts from the SVS crowd. For now I'm happy, love my 30's and the rest.