Changing the beginning splash image?

I’ve heard that this isn’t legal to do, so I’m wondering if an exception could be made.
The splash on every unity free game doesn’t really fit with the colour scheme of my game, so I made this instead:
The image

I need an official to tell me if I can legally change the default splash to this.

I’m no official, but the short answer is you can’t. Changing the splash image is a pro only feature. Changing Unity’s logo is pretty much a no go.