I agree with everyone above and would only add that for large, heavy speakers, forget the original shipping boxes, custom crates are a must. The cost to build them (materials, etc.) should be included in all calculations. I had a pair of Tannoy D-700's shipped to me that met with the UPS forklift and fortunately didn't suffer damage becuase they were packed so well in a custom made crate (thanks again tbadder). Pack with care, nobody cares about them like you.
Mike.