Interesting post. I've read but I just see that you've got an 25Mhz version of an 030. Because I would mention that I played mp3s for years on my 030@50. Just play it on half rate (22050hz), mono (saves a lot of speed!) and then try the best quality setting. AFAIK was it option 1 (0,1,2).
Good luck, let us know :-D
Oh and, i use amplifier and/or prayer. Those are the fastest. Don't let you get distracted by the programmer of Prayer which claims she's a photomodel. It's just a "marketing" strategy ;-)