I have a mewtwo and it has a modest nature, perfect IVs, and max EVs in sp attack and speed. the remaining 4 go to HP. the moveset is thunderbolt, flamethrower, ice beam, and aura sphere. held item is a life orb. is this good?
Yep, pretty much your typical Mewtwo.
2 things:
Try and obtain a Timid Nature Mewtwo. Modest makes it get outspeed by Pokemons that are necessary for him to outspeed.
Go with Psystrike > Flamethrower / Aura Sphere. Chansey & Blissey can be a pain to deal with.