Thank you for the website links, but I'm mostly familiar with the beta stuff

Anyway, let me ask you a question... here's the deal, ppl claim (including yourself) that the "Cougar" is only a beta model of "Virgo". "Beta" assumes that the Cougar came BEFORE the Virgo, so that the Virgo got developed later, right? Anyway, here's a catch... Like I said earlier, on one of my previous posts, the "Cougar" is mapped with Virgo's textures. No need to replace anything, not even to rename any of texture IDs, everything's completely similar to the Virgo! Therefore, if the Cougar really did came before the Virgo, that would be impossible...
Obviously, Virgo already existed at the point when Cougar got developed, and for some reason got included in the game archive. Who knows, maybe the Cougar was supposed to be some kind of a experimental project, to include more cars that share the same textures? Come to think of it, reminds me of the Corpse Manana & ordinary one from GTA3...
IDK, you decide. But somehow I doubt that the Cougar was a beta model. Not only because of the Virgo's textures, but also because of the name itself... Why giving 2 different names to the same car? But it all comes to what I said above, even if the Cougar really was some kind of a beta leftover, that doesn't explain why would they name the car that way, if they already assigned Virgo's textures, which means the Rockstar already came up with the name Virgo.
My guess would be that the Cougar was supposed to be a special version of Virgo, used for a mission. They probably took out that mission in the final version and so there was no longer need for the car. Which would also be the case in GTA3, if they decided to take out "Dead Skunk in the Trunk", there wouldn't be any purpose for the corpse Manana