Not sure why it was there, I guess it's just so they can monitor where each code is from? Mine said "STI-RAGE-UK" and I bought it from Amazon UK. Did you buy it from something related to "EEXPRT"?
Also there is no custom install paths, sadly, as that's part of the DRM - it has to be on the same drive as the Steam folder.
Otherwise you need to make a system link between drives, though I can't remember how to do it.
A google search should find results for you about that!