I'm just getting started working on my Guzzi, I've got the manufacturers shop manual and from what I can see, the same basic theory of airhead bikes applies here, uncomplicated and easily maintainable by it's owner .
I've owned an Italian 4 wheel vehicle before, a '76 Fiat X1/9, trust me, there will be some things you'll find, that just don't make any sense what so ever .
In case you don't know what F I A T stands for, it's Fix It Again Tony !
Harper's Moto Guzzi in the Kansas City, Missouri metro area, is probably one of the best Guzzi dealers in the US .
I've gotten some parts from them and quite inpressed with their service, they came highly recommended from other Guzzi owners .
http://www.harpermoto.com/