Personally I would not create Carrara shaders for my Poser stuff. I already need to uv map and do image based textures for stuff so it works in Daz Studio. The same image maps should work in Carrara or anything else.  I have Carrara 5 pro and unless 7 is a big step up, would not really regard it as a modeller , but more like Bryce or Vue , a landscape creator.

You should be ok even if you dont like it if Daz 30 day return policy covers it , or maybe they will release a trial version.