Well, as far as our understanding of time-space work, traveling changing the past is impossible, and time-travel into future IS actually possible, but only at a depressing rate of 1 second per second =( It is theoretically possible to send data into the past, but that act is thwarted by the bootstrap paradox, but again, aside from paradoxical situations - quite possible.
To summarize nothing scary about option too. Option one, on the other, hand requires the rewriting all the laws of the universe, so changing the present looks at best like a mild inconvenience at that point =)