Mark Broadhurst has done a great write up on these bolt on ignition boxes. Its a long read, but go through it carefully and you will understand the advantages of each one.
http://www.lambrettaspares.com/info/mb- ... s+282.html
I've got an Augusto 700 and a couple of MTechs and there's nothing wrong with these, provided you set up your static timing to suit your engine. In my case, the Augusto unit doesn't feel right, but from one of my threads I now realise that i did not set the correct static timing so my engine laboured where I required the power.
Anyway, just got a Kytronic box, which after reading the above link, i feel is the best option in bolt on boxes. Hopefully will fit this this weekend and compare it with the Augusto that i will be removing.
Read about the Kytronic here.
http://www.kytronik.com/sb
As for your other questions, all you need is the standard SIL type electronic stator and the normal CDI. As for changing the "curves", both the MTech and the Kytronic have a slotted screw connection that you turn onto the next curve. But only turn with the power off. But it would be great, as suggested above, to have a knob on your headset. Perhaps this knob could automatically cut of your lectric power, turn to the next curve and then fire back into operation.