Vespa Kits - Resources
Below are some great tuning sites that deal specifically with Vespa /two stroke motors:
Worb5 from Germany - crazy modified engines...a complete nutter!
Taffspeed UK - Very reliable, reputable dealer.
How stuff works.com - Type in "two stroke" to understand the running of a two stroke engine.
MB Developments - Mainly Lambretta but they have some great Vespa pages too.
Malossi - Makers of kits for many Vespa models.
Polini - Makers of kits for many Vespa models (search under Piaggio).
SIP Scooter Shop - Great specialized and exlusive parts for tuning.
MacDizzy.com - Not Scooter related but shows everything you want to know about two stroke engines and tuning.