I have a VHS recording from late night BBC TWO in stereo of the film which was in widescreen but featured the original stereo recordings. The songs sound great, just like they used to, but on the 25th Anniversary DVD they have been re-recorded and sound different, and the voice of Rocky singing has been completely re-dubbed with a different voice actor and it doesn't sound as good. I'd much rather have the original version, hence why I won't be buying this when it's released if it doesn't let you choose which audio you'd prefer.
Oh, and I notice it's supposed to be a whole new 4k/2k transfer from the negatives. I hope this means it's better than the HD version that was on Sky Movies not that long ago. It looked horrible for a HD version of the film.