I just have to say that I finally decided to check this out. Running at 640x480x32 with 8-degree aniso and 2x FSAA on my Ti 4200, performance was very acceptable.
And wow, the game does look very, very cool with the updated graphics! At the same time, the levels really are poorly-designed for the new lighting, making too many areas just too dark. Now what we need to see is somebody take up the slack and design some new SP levels for Quake and the Tenebrae modification