I have an new M&K S-5000 THX system consisting of (3) S-5000s, (3) SS-500s, and two M&K MX-5000II powered subs. I love the MX-5000s and have had them about 9 months. My question is will SVS be making any THX certified subs, and if so, woukd they give an appreciable difference over the MX-5000? They really pound the chest and I'm really happy with them, but I'm a constant tinkerer. I could sell them easily, but not sure I want to unless the SVS subs are just a whole notch better. Would it be worth the trouble?