Quoting Starscream Soundwave
What do you mean by 'off by heart' because to me that means you know something really well..
That is correct! I know the F40 well, because I planed this. I studied a model F40 that I have, many times, and remembering all of it leading up to this. It is the first model that I built with nothing to help me nearby, no reference pics, nothing! Just the model in my head.;)