Thank you Red! I knew about cooling drag but not about exhaust heat. Mike never told me anything about it so I suspect he wasn't thinking about it. Here's part 1 of his visit with Alex Strojnik;
Mike and I talked a lot about this when he was writing this article in Sport Aviation. Sorry I had to borrow so much from our older movies - and everybody else - REMEMBER! - "Area Rule for supersonic - Arnold Rule for subsonic"