No you wouldn't want to Fade it, That would make the shading that shows up More smooth, Not the Jagged sharp colors that metal tends to have.Actually Fading it would make him look more organic, if that's what you want to go for.
What I did for this was Have 2 Solid Colors, Just Red and Black but with over 9000 more Jagged Edges.
His eyes are Yellow I thought that would look cool, but Black would be better.
I'll Release it when I fix that, I wish I could make it so that his eyes are always closed though...
Sonic is fun to mess with