Try
http://xfactor-updates.com/downloads/ to download MP3s of each contestant's performance each week. Basically... any performance that has been done on the show this year as an audio track.
All you have to do is register for free and download, nothing else, and it's nice and speedy. Worked great for me, now I have all the Jedward songs, it has every week. I might get some of the others' too.
I decided to make my own thread just in case nobody looked at the other MP4 one anyone!
Hope it works for you!