If you turn your headlights on as soon as you have enough room to pass, I doubt it will be useful for you, since I could block you right away, right? Maybe you meant as soon as you start passing me, right? If you do so, there's still a chance we will both crash, reactions aren't predictable. Shocked means more than just putting that "he is passing me, even though I have muuuch better experience than him!" face, right? One bad movement and we are both screwed, right?
Engine noise doesn't disappear when you turn your headlights off. Not because Initial D says it does. The noise will be heard all the time. If you are too far for me not to hear you, you are also too far from me not to see me driving around corners, with my tailights on for you to see me driving the course (as Takumi did

). Therefore, your only chance will be to be close to me to see me drive, at which point I can and
will hear you, and therefore be careful not to let you pass.
I can't believe I went this far with an argument with an Initial D fan, really. Congrats. I won't even bother to go further, because this has no end, and I know how it sounds: "he can't drag the argument further". Maybe I can't, but it's stupid to ask things based on an anime.