I originally thought XNTP for you, but here are some more questions:
Describe how you apply your willpower to your world.
What are some of your goals, and what are some of your accomplishments?
Do you like to take things apart and put them back together? Do you use this ability to figure out how things work and troubleshoot?
Do you like driving fast or taking physical risks?
Do you relate more to inferior Fe, Si, or Se?
This may rule out INTJ for you. I'm also doubting you are INTJ because you really seem to use Fe and not Fi. I have not seen anything resembling Fi in you. It may also rule out ISTP because they are very physical in how they apply their Ti. It's not just about physical use of the body, but they use Se in conjunction with Ti- which means their ideas and logic are more oriented toward the physical world and concrete reality than metaphysical ideas and ideas for their own sake. You really seem more Ne than Se to me, because when I've listened to you talk you bounce around from idea to idea, whereas an ISTP will almost always apply what they are talking about to something concrete sooner or later. ISTP's feel free to moderate this description, but this is my experience with the type so far.
I will read this entire thread at some point, so sorry if some of these questions have already been asked and answered. Also I'm not ruling out INFJ for you. I don't think you seem like much more of a Thinker than me. I think it is much more likely you are INFJ than INTJ, since your Fe seems so prominent.