An MP3 CD is basically just a "data" CD. Burn the MP3 files to a "data" CD.
MP3/Data discs are not speed sensitive. However, regular "audio" CD's need to be burned at a lower speed to be compatible with older audio CD players. I have a recording studio and also burn CD's for users for sale (I have a bank of 5 CD burners that I use and can burn 5 CD's at a time, using Nero Burning ROM that will burn to multiple drives and I use ink-jet printable discs and print CD labels with an Epson printer). My audio CD burn speed "standard" is 8X. However, most SATA CD/DVD burners will not go lower than 16X and that can be a problem for older audio CD players. My audio CD burners are PATA (IDE) and they will burn at 8X. I've burned hundreds of audio CD's for customers and none have reported any complaints, however, I have heard complaints of skipping or not playing with audio CD's burned at higher speeds.
I have found one model LG SATA CD/DVD burner that will burn at 8X, it is a LG GH24NS70 model. I haven't found any other SATA drive that will do this.