Poser4 has always been quirkey in Classic on my system so I quit working with it. However, P5 and Transposer work great though. It's easy to recommend spending your money... :) I've spoken with others that have been using P4 and Transposer with no issues though. With both Carrara and Poser open, updating a Poser document will not automatically update the Carrara file. The Carrara document must be closed and reopened for an update to occur. So, I guess I'm trying to say, there may not be an advantage to having access to both programs at the same time. Outside of the annoyance of quitting and restarting programs, that may simply be your best bet. :(