After reading these part of the article:
The first problem was this one bit in the waveform data for one of the PCM ROMs that is always on and the ROM itself was mass manufactured with it that way. In other words, one of the ROMs in the production version of Out Run has corrupted wave data.
so we burnt a new ROM with the sound data and recorded off of that. So the issue is fixed in that soundtrack.
is there some way to get ahold of the non-corrupt rom? or is it already been released?
The part about splash wave being out of sync also was interesting, but I doubt any mamedev would correct the 48 milliseconds delay (as a cheat).