Watching "Arena" last night it occurred to me that while efforts have been made to update the special effects in TOS , some of the dialogue could be subtlety altered to bring it more accurate and consistent with both Trek as a whole and with the science involved. When Sulu reports that the Enterprise is 500 parsecs away from where it was I thought that it would take a very long time to travel that distance even in the TNG era. We see a similar example in " That which Survives " with the 997 plus light years the Enterprise was tossed. I am sure we can all think of other examples of this. To me the heart of Trek is the story of a more enlightened future and the exploration of both the unknown and human nature so a bit of sound effects sleight of hand to fix some of the more glaring distance and speed errors would not bother me but I would enjoy hearing others opinions on this.