I tried that Convert thing just now, it doesn't recognize the format, says " no files to convert", and ADS isn't listed as one of the supported formats.
MistaY, sounds like you might have the ticket in PS2 tools.. is that a small thing that's emailable, by any chance? At least the audio portion, don't really need the rest of it.
And yes, I used the "extractor" from the RipKit, used for modding the GT4 files to unlock the tracks, etc. I don't have a DVD burner, or a modded PS2, so those changes don't do me any good, but the extractor did work on the US Toyota Demo disc, which is where I found the audio files (which is why I extracted it in the first place, looking for nice full-quality versions of the soundtrack).