P4 uses BUM files in the Bump channels. You might have some problems with products and freebies that reference a jpg in the bump channel (as PP and P5 use the jpg). You will not be able to take advantage of P5 specific stuff, like dynamic cloth and hair; shaders and nested folders. If the tnails are in png format you will need to either resave the item to get a tnail or use P3DoExplorer (free version is out there) to convert them. And you can out put a texture map from the obj files using UVMapper (which is free) and you can paint new textures using Photoshop, Paint Shop Pro or some other graphics program (like the GIMP, which is free). Take the time to get to know the Poser file formats and which folders you can and can't move or rename, it will save you much frustration. Scrounge the freebies for goodies. And welcome aboard. :) Hope that helped some. --Rebekah--