It really depends on what you want from an ignition. If you want true advance and retard timing and high electrical power (over 150 watts from the get go) your options are limited. Ignition advance and retard isn't going to give you a huge performance boost but it does give you a good margin of safety as the rpm picks up.
Have a look at the following: http://www.granturismo.pwp.blueyonder.c ... nition.htm
This isn't the simplest of ignitions to fit, because it doesn't paper over the significant cranks in the rest of the Lambretta system. It does mean fundamentally changing how the scooter electrics work. That said, everything is explained well, a bit of research on the internet and access to some tools and you can do a very large amount of the work yourself. Everything is covered in the manual and pound for pound you get a lot of technical features, flexibility and opportunities that have not been available before like rev counters, power valve options (servo and solenoid), temp sensors, lap timing, fuel lights, very powerful lights, auto advance and retard etc.
