Using COG 8.1.4 on Mac OS X 10.5.8 (NVidia) TRL runs great without graphical glitches so far as reported earlier. The only problem I had was, that using the default screen resolution (1024x768) the mouse pointer always moved upwards in the game menu. Using the setup program I merely changed the resolution to the max (1440x900) and suddenly the mouse pointer was working properly.
Played now for 2 hours (still in Bolivia ;) and all was working fine.
Great (again)!