Autospeed from Australia installed a small turbo from a twin turbo Subaru into a first gen (97-99) Japanese market Prius with very good results. The first 4 parts chronicle the built with all its frustrations and failures. Part 5 focuses on power gains and fuel economy. I found it every interesting. It also shows how much the third gen Prius has improved over the first 2 generations.
part 1
http://autospeed.drive.com.au/cms/article.html?&A=2658
part 2
http://autospeed.drive.com.au/cms/A_2659/article.html
part 3
http://autospeed.drive.com.au/cms/A_2660/article.html
part 4
http://www.autospeed.com/cms/A_2661/article.html
part 5
http://www.autospeed.com/cms/A_2664/article.html
EDIT:
Oops, this belongs in articles section. Somebody please move.