Hoooboy.... In order now. 1.Yes you can. Even on different hard drives. It's slightly easier on the Mac to do that. In fact many users had both on their systems when it first came out. As for conflicts the only one I can see if you click a PZ3 file it might open one or the other. 2.I think if you just load the Geometries from P4 into the P3 folder it should work. The conforming clothes won't work as poser 3 doesn't have that feature. But if that's the case there are quite a few combined characters out there. 3. Meta won't but Ghost Effects (the programmers and owners)are currently tweaking the "Beta version" of the Poser 4 Patch that was release at Christmastime. It should be out "anyday now" They want to have the patch available on Meta's website, but for now they are the sole support for Poser4. I hope that helps you some. Nick