These are high(er) poly versions of the original 'grey
textured pipes.
They've been tested in Thief 2, but they should also work in Thief 1/G.
They use the original textures.
Note that although the preview screenshot only shows 1 pipe (original and new),
there are improvements for all 8 pipes.
You can download the objects by clicking Here
There are installation instructions in the .zip