I've been looking for a better stove. I have a BK Princess on order, which got damaged in shipping. I am now in dealer limbo as far as if/when I get my stove. Anyway, I was surfing craigslist and found what appears to be deal on an Encore. He says it's about 20 years old. How efficient are these old cat encores? What is it gonna cost me to replace the cat? Can it be used with my 6" chimney? If it's a decent deal, I may use it or set my parents up with a stove.