
WAV -> MP3 -> WAV conversions result in files of slightly different sizes because various encoders and decoders insert/remove very brief bits of silence at the beginning and/or end of an MP3 file.

The OTHER thing with iso/mp3 rips is that when burned back to disc, the audio tracks won't land exactly in the same spot they are in on the original disc. MP3 is after all the compression format of choice in its own right, and unless some idiot thinks ripping CD tracks to 96kbps MP3 files (or less) is a cool thing to do, the audio comes out just fine. Iso/mp3 images differ in sound quality for one thing, yes, but very little if at all.

Bin/cue images are a 1:1 representation of the original CD and will result in a 1:1 burned copy.
