http://www.palmdigitalmedia.com/product/reader/detail/4
the reader automatically comes with the ability to read dictionaries and a copy of the webster's vest pocket dictionary. you aren't required to install the dictionary to use the PRP, but you won't be able to use the reference and lookup funtions without it.
One of the compelling reasons to get the pro version is the dictionary. why do you feel the need to upgrade if you're not interested in using that? is it really worth the $15 just for color customization?
d'oh, looks like Alexander managed to post his response while I was composing mine. Anyway, yeah. um. so why did you want to upgrade without the dictionary?