Stats

Armor, magic resist, mana and attack speed are the same at every star level.

Soraka

1 star: Calm the area around the enemy with the highest current percent Mana, dealing 200 magic damage and Mana Reaving enemies within a 2-hex radius. Mana Reave: Increase max Mana by 35% until the next cast.
2 star: Calm the area around the enemy with the highest current percent Mana, dealing 275 magic damage and Mana Reaving enemies within a 2-hex radius. Mana Reave: Increase max Mana by 35% until the next cast.
3 star: Calm the area around the enemy with the highest current percent Mana, dealing 400 magic damage and Mana Reaving enemies within a 2-hex radius. Mana Reave: Increase max Mana by 35% until the next cast.

7 patches changed Soraka, read out of Riot’s game files.