I am considering the Lopi Declaration series wood burning insert or the Quadra-Fire Voyageur insert. I was wondering if anyone can tell me why the BTU rating on the Quadra fire is only 43,000 btu vs. Lopi Declaration at 73,000 btu. I thought it may have something to do with the way the firebox was designed or something. I know the Lopi utilizes a secondary burn system so maybe that is where the gains are. That is a huge jump in efficiency so I want to make sure I am making the right decision when choosing which one I will finally purchase. Thanks for every ones input.