rejzor: I just wanted to ask about this and I don't understand why they don't include S3TC textures in the base game. I mean, when I bought UT99 back in 1999-2000 I got it on 2 CD's. One was the game and second CD contained S3TC High Resolution textures. I still regret lending the game to someone and that someone never returned it to me.
It's annoying to hack the whole game and then file verification on system reinstall resets everything. It's not a mod, it was an official part of the game and considering all graphic cards today support S3TC textures at insane speeds it would be stupid not to include them by default because they were really insanely detailed. Rocket launcher and machinegun look like they don't even have holes in front with default textures, but with S3TC you actually see them in great detail.
Not sure on GOG's reason but there is an unfortunate issue that occurs (with CD2 S3TC textures installed) online with servers that use the textures included with the ut linux server package. What happens is that when you join the server all the players appear to be skating instead of walking properly. This can be fixed by using the default textures instead of the cutdown ones but its up to the server administrator to fix.
At OldUnreal they did find a way to fix this so all the S3TC textures there will not exhibit this issue but it will still effect CD2 and old versions of the UTRP textures.
My guess is that because there are newer versions of everything on CD2 they didn't bother to include it.