If this is true, I would like to enter a detailed discussion of this topic with someone knowledgeable about it. I might be interested in writing a program that does this.

I was under the impression that the MP3 frames were encoded in such a way that prevented this kind of manipulation.

What can you tell me about this? Can it be done simply by locating the proper bytes and altering them? Or would a lot of math be involved? What do you know?