Object changing scale in Rendered mode As you can see from my model I am very new to blender, but I feel I'm progressing well. But this problem is slowing me down as it's very distracting.

I have a scene with various parts and everything lines up fine  in all modes except Rendered. I have made sure I have deleted all keyframes, and hit ctrl-a to apply LocRotScale where I want it, but as soon as I go to rendered mode or try an actual render, the main cube seems to get smaller so then nothing lines up.

I have searched a lot for a solution but only found the obvious answers, which haven't worked for me. I have even remade the cube again but I still get the same problem, which just confused me even more. 

Can someone please cure my noobness??

Many thanks.

Update: Here is a link to the blend file. Its more than likely terrible so please don't laugh :) 
https://drive.google.com/folderview?id=0B8cLVpkzaATbcDM4YUJhZzFFV28&amp;usp=sharing
You have enabled Warp in the Influence panel under Texture.15's tab



With that map you are displacing the geometry's vertices. I can't tell you why a Wrap with 0 influence mess all up and disabling it fix the problem, but is definetly that option that you have to check.