u can only get it when you had beat the elite four at the end of a cave
Mewtwo X is better at Attack and Defense than Mewtwo Y.
No, there isn't, just different pictures.
Mewtwo is at level 70 when you find it on leaf green.
I would say either, Charizard Lvl. X, Mew Lvl. X, or Mewtwo Lvl. X
he is level 70
Mewtwo is at Level 70 when you battle him. You should most likely use you highest level Pokemon that is around level 70.
Mewtwo can Mega Evolve into either Mega Mewtwo Y or Mega Mewtwo X.
Mewtwo learns Aura Sphere at level 93.
70
70
Mewtwo doesn't learn Psybeam.
You find him at level 70.