I extrapolated a 16 bit MP3 to 24 bit, when I injected it into Cubase. But then the audio file was a bit longer than when I don't extrapolate. And, the audio sounds really bad in places. Then, I tried to time stretch the other tracks, to fit an un-extrapolated MP3, and then IT sounds like shit! Apparently, this time stretch function doesn't work well in Cubase LE 4.