| The IRS was talking about their right to read our
  | email four years ago. The IRS has no known
  | infrastructure to pull that off, it's clear they
  | were talking about NSA or FBI programs.

I seem to remember that this was about their ability to just walk up to Google and request someone's emails without a warrant of any sort. There's no implication that it has to be related to some NSA or FBI program. Assuming that the NSA has every email ever written in storage, I doubt that they would coordinate with something as 'mundane' as IRS tax collection. They are a spy agency after all, and their purview is National Security.