I remember a handful of posts regarding installing DimPro and the included expansion packs in the X2 download area. But now I can't even find them so I'm posting this here in case I'm not the only one who didn't get the memo.
I emailed tech support about what to do if I already had DP 1.5 and the original expansion packs 1-3 installed.
This was their reply:
"Dimension Pro and its expansions are the same in X2 as they were in X1, therefore you do not need to run those installers if you already have it loaded."
So the installation process just got that much easier. Wish I'd known that before downloading DP and all three Exp packs, but what the hell.
Hope this helps someone.