For you resourceful types, you may find out on you own that you can bolt on a K26 compressor to a K24 turbo that is found on some 1.6TDs
Don't do it, it doesn't work well on a diesel. I tried it, and its definately not an upgrade.
The boost comes on slower, and if you go over 10 PSI the air is heated up significanly.
See:
http://www.vwdiesel.net/forum/index.php?topic=20805.0
in the french section a man instaled a hybrid in audi100 2.5tdi