You could atleast provide input on the topic. It may have been an over exaggeration, but opening the eigth gate wouldn't be too far off it. It's stated they can surpass the power of Kages'. But yeh, it's unlikely anyone can travel at the speed of light (Kizaru maybe). Maybe sub-sonic speeds is more accurate. As for evidence, what do you need? Here's my train of thought. Noting I haven't even seen the show (only the manga and that was months and months ago) You have the Raikage's that can go the speed of light (evidence? They can leave after images of themselves) and they use their lighting power to enhance their speed. Naruto was suppose to be just as fast when using Jichiriki form They all struggled to do much to Madara in the final arc Guy Sensei was able to do alot of damage to him when opening the eight gates. Without going into mathematics and physics. You tell me what speed he is going at to be describe what I am trying to explain?