Hello!
As you can see from this picture of the headunit/nav circuit board, there are bulbs, covered with blue rubber cap, which produces yellow light+blue filter = green effect. Changing them with diodes is not easy, mainly because you can't get the diodes to flood the light the same way. And as discussed above, every segment has its own shade and different solution.
But you can change the LED at the bottom middle and get a differnt CD indication.
link
Andrej