Modeltrainman,
If you could get the following files from Alien Crossfire: sid.flc, sid.pcx, sid.txt, sid2.pcx, sid3.pcx (or brian.flc, brian. pcx, brian.txt, brian2.pcx, brian3.pcx), you could play the firaxians.
You would have to put those files in your Alpha Centauri directory.
You would also have to modify your alpha.txt file under #FACTIONS by replacing one of the 7 factions with
SID, SID
If you can get those files, I would be willing to work with you to get it to work, but I would prefer to do it in the
AC Creation forum at Apolyton.
Modifying the alpha.txt file is better discussed in that forum than here. And there would be other people with the necessary expertise there.
Provided you can get those files, I don't see any reason why you can't play the firaxians in the original game. The faction file sid.txt does not have any SMAX only characteristics.
There are some paragraphs at the end of sid.txt that only apply to SMAX
#ALIENFACTIONTRUCE and #ALIENFACTIONTREATY
but these were added to the original SMAC 7 for SMAX, so I'm sure they could be taken out so they are compatible with SMAC.