FCP doesn’t like anything except WAV or AIFF. You can get mp3s to import, but they are generally too low quality and have to be rendered if you want to hear them.
And if you’re doing this as a personal project and don’t plan on making money off of it, you can use the purchased songs, but as soon as you try to make money off of this project with purchased music, you will be in BIG BIG TROUBLE!
My advise to you is to make some music based on what you downloaded using GarageBand. It’s a lot easier than you would think (even for a non-musician such as myself). Of course if you have the money to buy the rights to those songs, or to pay someone to create new music for you, then by all means do that.
Winston A. Cely
Editor/Owner | Della St. Media, LLC
Mac Pro 3GHz Dual-Core Intel Xeon
4 GB RAM | Final Cut Studio 5.1.4 | Aja Kona LHe
“If you can talk brilliantly enough about a subject, you can create the consoling allusion it has been mastered.” – Stanley Kubrick