This statement has a dual meaning. First that Eminem is feeling a buzz from this hit song. And second, that he had to be taken by ambulance because buzz is phonetically close to bus, which can also mean an ambulance.
This gentleman is trying to say he is single and wealthy: no wedding band on his ring finger, and he owns a BMW M3, a light-colored Range Rover SUV and a very white Cadillac (white paint, white trims and white interior).
"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.
While Kanye has been very succesful in terms of musical awards, he would be willing to trade in his Grammy Awards for his grandmother to come back to life. He is showing that while awards are important, the esentially are worthless in the face of family.