Buffy's hairstyle changes after Faith inhabits her body from straight to loose curls (crimped), and Faith's hairstyle changes from loose curls (crimped) to straight, in which no other character notices, (especially Joyce).
Buffy (in Faith's body) stakes the vampire Boone from behind when it is attacking Faith (in Buffy's body), revealing her standing there when it dusts. This scene echoes Faith staking Mr. Trick in Consequences (1999).
Faith (in Buffy's body) states that "Faith's" arrest was "poetic justice". This references Faith and Buffy's confrontation in Graduation Day: Part 1 (1999), in which Buffy states that sacrificing Faith's blood as a cure for Angel would be "poetic justice", as Faith was the one who poisoned him.
Faith (in Buffy's body) comments on Xander's sexual performance, about which she gained firsthand experience in The Zeppo (1999).