Some of the xicon resistors in the batteries are no longer available. I recall there were some other brands that people had success with, but that for the most part if xicon's weren't used in the batteries you would end up with a noisy t2. For someone like icarium he needs to make sure the large caps are short enough to safely fit in the case without being accidentally hit by a case screw. The one in the original bom is no longer available, though alternatives are probably out there.