1) to be honest, i dont know, i just used some quite thin multi strand wire i had lying around. if you take a look at the jumper wires inside your computer, about that size is the one you want
2) again i dont have a clue how much voltage is traveling down the wires, next to nothing i asumes as it is coming off the mobo, a guess would be less than 5v but i dont have a clue. no, all the power coming into the pooter does not go through this circuit!
3) i got the key from a good old friend of mine called ebay. this looks almost identical to mine, and it already has the wires attached [URL]http://cgi.ebay.com/Key-Set-Switch-Wire-ignition-Electric-Gas-Scooter-Parts_W0QQitemZ130010649721QQihZ003QQcategoryZ1133 2QQrdZ1QQcmdZViewItemhttp://cgi.ebay.com/Key-Set-Switch-W...QQcmdZViewItem
disclamer, if you buy that switch and it is the wrong one, i cannot be held responsible!! lol