I do have a related question:

I am playing under Vista, works ok, I have RTW Gold installed, and then installed EB, so I guess it's using RTW.exe now and I get a huge load of CTDs at the moment.
Will switching to BI.exe change that? and what effects does that have on AI behaviour?

I don't have Alex, and if I bought it I probably wouldn't play vanilla Alex anyway, does it make sense to get it, just to be able to use ALX.exe for EB for stability, CAI, BAI, DAI?

Also, I guess I can still use all savegames when using a different .exe, right?