I'm speechless.. I really am. Did they seriously think that no one would notice these assets? I mean.. the comparison shots just make me LOL for real.. seriously. Even if a non-profit modification did this it would still be beyond wrong.
On the subject of the Stalker/Crysis mod, that's technically legal since GSC have allowed their content to be used in other titles, so long as it's not for profit. Kinda talentless though ripping entire sections from one game to another if you ask me.