[grotesqueness]

If we take Einstein theory, that we cannot exceed the speed of light, then time travel is impossible.........

Einstein is right
but Einstein is right because we are bond by the physical means we have 
we cannot exceed the lightspeed limit

yet we can exceed the light speed limit by manipulating time
and einstein is not wrong on the speed of light limit
he did mention his time dilation

this give us a clue on the existent of the conscious universe  we see

and there are other so called "parallel universe" we can only see if we manipulated time 

einstein is not wrong
nor the quantum physics 

the problem is the physical properties of time as we knows causes our failure in understanding the two



if you want to live forever
you got to understand the consciousness on time 
the first question is 
what is time really is?