How do Em and Nikki's experiences at Tribeca Alternative High School differ in the novel, Airhead #1: Airhead?

Tribeca is run by a popular crowd, one Em isn't a part of and Frida wants to belong to. Tribeca is in Manhattan, NY. Christopher also attends Tribeca, where he and Em eat lunch together and have speech class together. After Em becomes Nikki, she decides to go back to Tribeca Alternative so she can keep an eye on Christopher and Frida. Tribeca is a bad experience for Em, but a good experience for Nikki.