GW is "Greywolves" and GWX is Greywolves Expansion" (not yet released),funny that I tell you this, 'cause I haven't got GW yet.
BTW, all harbors aint deserted. I play stock SH3 and I've seen ships in Port Said, Loch Ewe, Scapa Flow, and Hartlepool. It aint much, and I got a bit pissed when I visited Key West (!!!!) to find nothing......
I'll get the GWX when it comes out, until then, I'll just play stock.