There is
this which seems to be the old winamp plug-in that claimed to support aifr files (it also tries to handle other aifx based file types which might break things).
There's also meant to be support for those files via vgmstream (which is already included with wacup) but 'aifr' isn't something that it's setup to recognise so without files to try out that could just be a simple code change to allow that plug-in to handle them or it might need more work if the support within vgmstream isn't as I'm currently led to believe. Otherwise the remaster is easier to get.