Installed CXG 8.0.0 last night, first thing I did was install PWI.
Ran the provided Download Client as "Unsupported Software", it grabbed all 3 GBs of the game, and let the installer Run.
Took a LONG time, but I was also using the Mac for other stuff at the same time. I found the update to take an extremely long time also, but there were several updates to pick up, so that might be a contributing factor.
Game runs flawlessly. As fast as when I run it through XP on bootcamp. Most Graphics Settings on High, a few on medium.
Running Windowed Mode, stretched to "full" Screen.
Macbook Pro 2.4Ghz, 4GB Ram