I always found immersion to be the best way to improve my game. I didn't adjust my head position, didn't make custom gunsights, didn't reduce sound volume, or anything. Being there, feeling like I was really in that environment, helped my flying a lot I think. I tried flying with the sound off a couple of times, but I found it too silent and disconcerting. I guess I enjoy flying with some kind of "white" noise in the background.
Honestly, though, I don't think that the difference between having the engine on or off -- or raising your view as high up as you can get it over your nose -- are so great as to constitute "gaming" or cheating in any way. You're ultimately going to fly best with your game set up in the way that you feel most comfortable.
-- Todd/Leviathn