1) as long as your not a noob (which your not) there shouldnt be any real weak point that anything will break unless you hit something
2) i think there is only one version of the lightning but i could be wrong
3)im not sure about the tires, but it is a 12mm hex
4)200 mm bodies will fit, and i know that justin did put a 190mm body on his too
5)and yes the sh will be a direct replacement

i actually dont own a lightning (yet) but my answers should be accurate from my knowledge cruisin around the forums, are you gonna be racing it or just bashing around (curious)