NECA T-800 modification

I was browsing ebay and found a 1/6 scale endoskeleton by NECA (National Entertainment Collectibles Association). It is a collectible item, but it looks and feels like a toy. I mean, It looks pretty good, but it could become even better with some modifications. I want to get rid of the toy look and improve details.

I searched youtube, and found this.

This guy was doing what I wanted to do. So I tried to make similar modifications myself with the materials I had at my disposal.

Improvements I want to make

So the first step is to take it apart.