Was finally able to pull the trigger today on my P35i as i've been dwelling on it for 6 months, my Harman dealer was running a summer special so decided to take advantage of it (Really impressed with the stove quality) I also purchased the OAK and the harman spacer that will allow air into the flue for the OAK. Anyway I need to buy a chimney liner and was wondering where the best place to go to.... my chimney flue 25' long but would like to get a 30' long just to have some extra slack. Need 4" dia. and would prefer 2-ply 316ti, from my research it doesn't seem necessary to insulate so I won't bother with that. Also as Im drawing outside air from the flue , would I also need a short section of 3" chimney linear quality pipe to shove past the block off plate? or will any kind of metallic flexible pipe do? I've checked eBay, chimney linear depot, rockford, and they all seem to have the same stuff with about the same prices for the kits (top plate+cap and insert connector incl.). Is there any difference here between what these guys sell? I want a quality linear that I wont have to worry about but I also don't want to get ripped off. If anyone here has any recommendations for online suppliers I can order from that would be mucho appreciated.