Here's the word:
EG 4.3 will support SAS 9.2 (as it does) and SAS 9.3 (when released).
EG 5.1 will support SAS 9.2 and SAS 9.3.
Same goes for the SAS Add-In for Microsoft Office (4.3 and 5.1).
There are just a few 9.3-specific features that won't work when using the 4.3 versions of these clients.
Chris