You can not take someone's property that's stealing
Copyright infringement is a serious federal & musical crime. With the advent of the net and other medias it is much easier to be caught doing such things.
You can not take someone else's property and use it for gain that's like someone taking your car without your permission, going to New York to make a delivery, getting paid for that delivery, and after doing all that not returning your car to you nor ever giving you a piece of the money that was made. That's stealing.
If you are trying to do a demo you need to invest in your future. Pay your dues because they will be paid one way or the other!
Jay-Z had to invest in his career, creating his own sound and identity to be heard so if you are attempting to model your career around him, you have to find local producers or on the net that you can afford to be produced by.