There seems to be some confusion about which one has a better R value. I found some comments on this board that say Micore 300 is better, however, if I read the Technical Data Sheets correctly, Micore 160 has better insulating properties: Micore 160: k-factor: .39 R-value (1/2" board): 1.27 Micore 300: k-factor: .49 R-value (1/2" board): 1.03 To my knowledge, a low k-factor is good, because it means less conductivity. So it seems to me that Micore 160 would be the better choice. However, and I am also weighing those factors, Micore 300 is mechanically stronger, which might (I am not sure if it would) be a factor when using it under tiles (with CBU over it, over course). Anybody have any insights on this? I'm right now facing the choice of ordering one or the other. Thanks everybody.