Here are some links to refer to that may help ask the right questions
http://www.lcgb.co.uk/workshop/buying.html
http://www.lambretta.co.uk/models.html
http://scootrs.com/comparison.cfm#Asia-r
http://thekneeslider.com/archives/2006/09/15/vietnamese-scooter-restoration-update
Does this Site Suck or What?