What are the major differences between the anime/manga and the live action version of Perfect Girl Evolution?
According to the Japanese Wikipedia, the main differences are:


  
  Kyouhei becomes the main character. Sunako is listed as the 3rd cast in the credit.
  Kyouhei, Takenaga, Yukinojou, Ranmaru, and Noi are high school students in the original work, but they are undergraduate students in the TV drama.
  Mine (Sunako's aunt; the landlady) doesn't have children in the original work. However, in the TV drama, Takeru is introduced as an original character playing the role of her son. He self-proclaims to be the keeper of the mansion while she is away.
  Shinichi, the master of the coffee shop (Meykuu Iri, "Unsolved") that Kyouhei and his friends like to go, appears as a regular cast in the TV drama.
  Compared to the original work, Sunako's personality is sharply changed. Even with the usually timid and negative personality, when Kyouhei calls her Busunako (Extremely ugly Sunako, from busu + Sunako), she will display her paranormal-thingy and high fighting power and also her personality becomes stronger.