Some of you cats just dont know shit about the music business. Do you think 40 could just tell the label what single he wants to be next? Its not that simple. There's actually a process to the whole thing. There are many factors that come in to play when choosing the next single. A few tracks are sent to all mixshow dj's around the country and then weekly conference calls are made with various dj's to discuss how each track is doing in terms of request, positive feedback, club rotation, how well it can be mixed in the mixshow etc.... The label also tracks the amount of downloads a track has on the internet (yes there's a way to track everytime a certain song is downloaded on the net). Mediabase is also a heavily used tool. There's a few more criteria but i dont feel like gettin into everything. Basically when all of this is done there's a big conference call with the vp's and heads of each department and they all fuss and fight until they come to an agreement of what the single will be. Thats pretty much it in a nutshell.
And just so you know the white gurl track got better numbers and feedback around the coutry than muscle cars did and thats why it was chosen. Muscle cars is a regional song. I heard with my own ears on a conference call several dj's from the south and east saying that muscle cars was gettin killed left and right.