I didn't read all of the post but i read someone them. I believe that according to modern physics that time travel is impossible. That being said i also think that modern physics is dead wrong. We have different models for macro, micro, and the world we live in, don't you think that the same rules would govern all of these, and not individual rules for the different scales. Also not sure were i heard this but i am pretty sure i'm remembering it right. According to modern physics isn't it possible to go faster than the speed of light, just not as fast?
To anyone that would likes to read about this kind of stuff i would recommend the book "Physics of the impossible" by Michio Kaku. It is a great book, although i am not finished with it yet.