Phase Technology PC 60 ca v. Teatro 7.5 vdt, PC 80, or original PC 60

Hi. I recently listened to a pair of PC 60 ca speakers and was very impressed. Not enough bass, but great highs and midrange, and a subwoofer can deal with that. But they are $1400, which is steep.
   I have seen used, Phase Tech Teatro 7.5 vdt for sale, floorstanding, as well as PC80, and the original PC 60 (markII?). All for less.
    Does anyone know the differences between these models?
    Do they all use the same soft dome tweeter?
    Am I likely to be just as happy with one of the older models? 
  Fyi, listening to B&W 685 speakers and sub, Denon rcvr with 80w/ channel.

    Thanks.