I'm thinking about buying a Buck Stove Insert to put in our existing fireplace. I will have to do the installation myself. Our firep[lace is a prefab with the individual masonry fireboards inside. I haven't looked behind these to see, but do I leave them in or remove them? Do I remove all of the outer trim and just replace with the trim kit? What about the electricity for the blower? I just need some information before I go and order one and get in and not be able to use it. The one I am looking at is the Model 21.