If the mod has a letter (e.g. 26B) throw it out. It sacrifices power and willpower for endurance. Even for tanks I'd throw out lettered mods, though that is a little more controversial.
Actually, the 26A mods go the other direction: they sacrifice Endurance and a little bit of Power for a lot of Willpower. Due to the endurance sacrifice, they have a higher DPS-affecting stat budget than the unlettered mods.