[Serum]

1) 1940, something at the 30-35000 rpm range
2) quark 125 or MGM 24160 (both have a built in lipo cut-off)
3) 6S lipo (though 4S would be enough allready, but you can take a lower kv motor and invest the extra 2S in runtime.)

Or you could do as Daniel (dafni) he bought 2 2S packs and 2 3S packs.

that way, you can run any configuration you like.