metal gears....approx $50 a set, in aluminum, as per a local CNC/FAB shop. I have a friend drawing up the CAD prints for the gear set. Gears should be cut by the end of the month. If they work well, I'll have a batch made for the DIY'ers. Also, I've contact the original maker of the moon roof (WEBASTO), hoping to bue module parts in bulk (another alterative). Waiting for their answer.