There is no general purpose to edit "SNES Music". All games used their own sound engines and they are completely different from eachother. Only games from the same company will use similar (but often slightly different) sound engines.
If you're intro Super Mario Kart, then you should look at Nintendo's sound engine, I'm pretty sure they are doccumented.
Also, as one of the major sound/music hackers here, let me tell you, you are wrong in beliving changing music is so complicated. If you are knowledgable about hex and music theory simultaneously, that's probably all the required knownledge. No need to even know assembly. It really isn't, not as simple as changing fonts or palettes, but definitely simpler than other kind of hacks.