Don't know anything about this seller/company. Here's my take.
1) Because they also sell straight 703, it seems like they may have some clue as to what they are doing.... MAYBE
2) They list their sound absorbtion ratings.... Assuming they are correct, (AND WE CAN ONLY ASSUME), there really isn't going to be much help as far as low end absorbtion, only mids and highs. If you need to work the bass out, this won't do much by itself. Another thing here... call them and ask where/how they tested their stuff to get these numbers... If they don't know, refuse to explain, or especially if they don't know what you're talking about when you say "Absorbtion Coefficient".... don't buy from them. Period.