Hi Paul, I can vouch for this system. I fitted it to my Jawa 350 and it works a dream. Is easy to fit about 2-3 hrs and it looks really well. Bonus's are - easier starting, no ignition points -therefore no timing adjustments,better lighting from 12v bulbs and bulbs are easier to get and cheaper.
You will have to change all bulbs to 12v, change the flasher unit to 12v and change the horn to 12v. You can see what the 6v horns sounds like but mine sounded like a cat being strangled so I changed it to 12v!