So long as you buy your own copy of P4, you should be fine. Poser 4 stuff imports with no problems into the latest version of Vue. If you are only able to find Poser 5 you may have trouble. I haven't had any problems in the last few days when I've imported pz3s created in P5 into Vue 4, but I have the latest version of Vue, and Poser 4 and 5 installed on my machine.