@Stanzi, yep, that summarizes well what has been said before in this topic. 
Yep, I also swapped my Toshiba Satellite Pro C850-1MW’s HDD to a SDD, and RAM would be possible too. They even have repair videos online. I rely on third-party batteries though since the notebook is already 4 years old.
At least notebooks should have standardized batteries. Internally (inside the housing) most of them use 18650 batteries anyway.