Sound better? or be louder? The 2 10's will be louder purely based on more surface area. Given the same amount of power that is. Given the appropriate box they should sound pretty much the same SQ-wise.
One thing you may consider is the Diamond TDX instead. Its less expensive, and to most people sounds better and has a similar look. There is a car audio shop in Iowa that has both brands and let people demo them side-by-side in a test car and most people choose the TDX over the W7 based entirely n sound. And most of these people came for the W7 and had never heard of Diamond Audio before.
