I used Love Attrage's idea, and here is how it turned out:
Did I miss a step? It looks like he plays around with some wires, but I don't think that should affect it. I used multiple layers of stickers, but I don't think that should make it this dim, especially since a bit of the tachometer is a fair bit brighter than everything else. Maybe they fell off? I'll of course be taking it out again soon to find out. It would be nice if I could find a fix. I'd really love to change the colours without having to solder new LEDs in.
Shame, I had a real nice write-up planned! I've seen multiple people change the colour, but no real thread about how. I was surprised in the pictures that I saw that orange light behind, let's say, blue would produce such a pure blue. Obviously, that is not the case.