Are you listening to SF2 Turbo instead of the CPS1-based SF 2 World Warrior? Probably doing the SNES a bit of a disservice since I'm pretty sure it just reuses the original World Warrior music. Which was also re-arranged for the SNES but those two are a fair bit closer. I'd imagine for the SNES ports, the arrangers had to deal not just with the more limited sound hardware but also the fact that the whole thing had to look and sound decent on everything starting from a crappy tv with a tiny speaker and up.