Great find Bruno! I haven't been there since picking up a lot of useful stuff about the Cali III a few years back. It's had a huge makeover, and the site has a lot more easily found stuff since I was last there.
Top level site here:
http://www.thisoldtractor.com/moto_guzzi.htmlNewly upgrade site, optimised for mobile use, and loads of data on all things Guzzi, including loop frames, Tonti and singles.
Also MGNOC site here:
http://www.mgnoc.com/index.html