I don't see a problem with it at that distance, But to be on the safe side you could fab up a nice looking heat shield, That's what i would do instead of wrapping the parts. Just build something that has a good look to it so that it don't look bad if someone sees it and you will know you made it . JMO
But if it makes you feel better wrap them up and add a heat shield it will still look fine. I have seen exhaust run from the factory on some cars and such that was pretty darn close,
But i know where you are coming from and i understand what you mean.
But i think a shied would do the trick JMO.