What is the biggest contributor to Poser file size?

I just found out that a product I bought cannot even be used in P9, cause of the size of it, and P9 is not 64 bit  (SM, where is that freakin sidegrade sale  >:O I am about to spend it all on Vue)....very aggravating.

Now I am very conscious of file size, and one file I have has just V4, hair, textures and clothes...and its about 200mb.