Busta Rhymes is declaring that he's the Top Gun (the best) which is the name of a Tom Cruise movie. He will then metaphorically "shut down your firm" (destroy you). The Firm was also a Tom Cruise movie, where he shut down a corrupt law firm.
"Weezy F Baby and the F is for Front do" (front door) Lil' wayne's way of saying that I am truly a gangsta that instead of robbing cowardly or sneaking into your house I will bring the drama to your front door.
During the time this CD was released, there was a huge debate on whether music, video games or movies influence our lives or childrens lives. "Slim" or Eminem was one of the artists under attack for violence and explicits in music.