could someone post examples of spectral analysis of mp3 compared to cdda?

The only sure thing you see there is the cutoff at about 16khz.

Create them yourself.

Start EAC > CTRL + E > open wav > display > spectral view.

Do the same for decoded mp3.

Why do you want to see them? Remember, with respect to lossy compression they aren't representitive of the encoders quality.

For some very bad quality mp3s, you might see big blotchy gaps in the higher frequencies which tends to give a metallic artifact.