Thanks for your reply! =)
In fact I only need to upload my game (.EXE + all game files) to Valve/Steam (no DLLs and files like this).
When I'm logged to their system then I can choose which redists users need to install before playing.
Right now I've checked two redists (DirectX and Visual C++) as extra downloads. I just need to know if I can uncheck Visual C++ or if it's mandatory to CC games.
But OK, I'll keep both redists marked until I find a way to make tests. Thanks again!