Will I kill the value of my Demon

the question really comes down to, if you are building it/restoring it for YOU or someone else? ie: flipping it at some point.
If your heart is not into the car and you truly dont see yourself keeping it long term, than value in being the most "original" it could be restored back to, would trump desire to make it your own.
personally, Id make it what color ya want, as long as its done correctly.