If the set ends with (NASY) or has GOLD in the title, then its is the lates Version of that set.
You can use whatever set you want. If you want the new set, then just download it, and only extract the images. They will over right the old ones.
One thing to consider is that the none NASY or none GOLD sets are just that, NONE GOLD. No Drones. This will cause errors if they are the only set you have. The errors can be overcome simply be deleting the AI files that are included with the 1.49 sets.
Or, upgrade the AI files with the GOLD Versions. I doubt this will cause problems with the PBW game, but if it does, we can always restart the game.
[ June 19, 2002, 15:09: Message edited by: Atrocities ]