It's just the version number. They have make some small changes in chip program. I read the chip program and i found some ASCII info from it:
V1: Tors function removed - only for racing
V2: Something about ingnition under 100rpm -> easy to start
V3: Input signals crossed
This is what i remember (maybe). I have all info in my other computer.
PM me your offer if you are interested.
-Reimond