[QUOTE = Edit: is there a difference between cable kits to be called "Road" or "MTB"? the only difference I can imagine overall length, but they seem to be the same length. And if MTB is more dirt-resistant, i didn't see that to be more expensive.[/QUOTE]

The difference is the inner cable will have different connections on the handlebar end for MTB brakes & shifters to road levers. MTB rear brake cable used to be longer for the disc brakes but now as road bikes are being fitted with discs I guess they maybe the same length, but still different ends.