Hi everyone, I began my build today. I've read where most of you tear out the door insulation and come back with Roxul and a steel plate. The old insulation looks almost like wood fiber. I'm wondering now if I shouldn't go ahead and pull out the tub too and Roxul the whole thing? I don't mind but I'd like to know there will be significant gains for doing it. ...aside from not want the whole thing to catch fire if it is wood cellulose. This is my first build and I"d really like to do it up right. Thanks for your advice in advance.