We currently have a 1970s Defiant with an 8" flue pipe (which we had installed in our fireplace flue). We are replacing this stove with a somewhat smaller stove. The pipe is 6". The stove pipe has to go into the wall aka old fireplace at a 90 degree angle--I am not sure how they do it (we are not doing it ourselves). Is there going to be a condensation problem? Are there any problems going from the 6" to the 8"? Someone at work suggested I have a 6" stainles liner put inside the 8" insulated pipe that runs inside my old fireplace chimney...is there any reason I should stick with an 8" pipe (there are not many models that use the 8" pipe...)? Any thoughts are greatly appreciated!