Just an observation. I got my copy of Tempest rising last night and it looks great. It manages to use Tau, tyrannids, and chaos in one massive adventure. However, I noticed that it uses the old rules for weapons. I was under the impression that the weapon stats in the errata were the "new way" and were made official in Black Crusade. However, it seems in the NPC section that they used the old rules for weapons (overpowered bolters, non-leathal Tau weapons).
Not that I mind, Tau weapons seemed rather powerful. I am guessing the designers knew that the players were going to fight lots of Tau and decided to show some mercy to the players.