Here's the link to the GameSpot article.
I've seen some of the PSX's overpriced single-disk-per-port versions of these games, and the entire "navi mode" is completely useless. Unless you like playing side scrollers with a blinking red arrow yelling "Keep going right!" at you the entire time. Until you actually feel like backtracking for something, at which point it starts telling you you're "going the wrong way".
AFAIK, the "remixed music" in the PSX versions could be turned off or on in the options at the start of the game. Supposedly halfway through the series of ports, Capcom got lazy, and stopped bothering including remixed music in them (making the later PSX ones COMPLETELY useless overpriced ports).
I actually didn't like the remixed music. It seemed out of place, and would just run for about a minute or two before stopping and having to restart (with loading times, of course). If there's no remixed music in the GameCube version (and I guess there isn't), then I can't say I'll care, but I do know that a lot of people are going to take shots at Nintendo's "insufficent" disk size because of it.
Edit: My bitter, Nintendo-hating brother was just reading over my shoulder, and is of the impression that it makes perfect sense, because the %$@* GameCube has no Dolby Digital output port, so there's no point in bothering to have remixed music in the GameCube version. I pointed out that it's most likely the remixed music from the PSX version of the game, and that certainly didn't need any Dolby Digital, but he just beliggerantly said that the PSX had Dolby Digital, and walked off, which makes me shake my head, but can probably tell you something about what the common idiot will think of this development.