Shawn: Just checking on my status updates. Check this one out. Shawn Spencer is trading in his Chevy for a Cadillac-alac-alac.
This is a reference to a line in the 1977 Billy Joel song "Movin' Out (Anthony's Song)". In the song Billy claims Sergeant O'Leary is "trading his Chevy for a Cadillac-ac-ac-ac-ac."