I am a do-it-yourselfer who owns the Haynes Piaggio/ Vespa service manual. The problem is, the manual doesn't get detailed enough for each specific vehicle.
There are plenty of in-depth questions that I have regarding my Typhoon 50 that are not covered in the manual.
From this site, I managed to get a parts manual. That's been a great help. It also blows the dealer's mind when I give them the exact part number for what I need.
I'm sure that Piaggio distrubutes specific manuals to their dealers (who don't like to offer one shred of information to the commoner). There must be a way to get my mitts on one.