Is it necessary to have the original Piaggio booklet to apply the modification?
no, not even for CIAOs modified at our Authorized Workshops. Given the downgrading to e-bikes, the manual is not necessary. It only demonstrates the lawful possession of the vehicle, but there are many CIAOs abandoned in garages and cellars, for which the owners no longer have the booklet because they have lost it, but which are, obviously, lawfully owned.
However, it is important that the chassis number is legible and that it has the Piaggio factory stamp, so that the originality is unmistakable.