The fuel question, not so much, you can run any fuel you like, they just run a little different and you may have to adjust your needle for the different fuel, but that's it. The thing is, is that once you get a fuel you like, you just usually get that type the next time. But that doesn't mean you have to. But if you change a lot, and you have a bearing failure or something goes wrong, you can't really blame the fuel, because you won't know which one did it!
You'll love the N5c, its a great heli! I have 2!!!