Car engines seldom hold full throttle for as long as we are WOT with our airplanes. They're also backed off a lot. Backing off the throttle cuts the heat input a lot. We don't do that "going into every turn" either.

So use any popular airplane fuel and you'll be ok.

Don't worry about nitro, as almost none of our airplanes actually benefit from more nitro than 5% or 10%. So save your money and use low nitro. Most people can't tell the difference. Because there really isn't much. Low nitro fuels save you money when you buy. And there is a slight benefit in gas mileage too. And engines last longer and are less apt to be screwed with a bad needle setting. For the average flyer who isn't flying pylon or precision aerobatics, more nitro than 15% is usually a waste of money. But beauty is in the eye of the beholder. So if you think a little more scream from the engine is worth it, have at it. Lots of room in this hobby for whatever trips yo' trigger.