Where to find Gmade spider gearbox?

Would anyone help me to find Metal gearbox and axle housing for Gmade Spider 2 please? The original plastic one looks very weak inside........

Thank you very much.

I think those Metal Gearbox and axle in the market is for Clod buster.
And actually you can do something very simple to make the original plastic parts stronger.

Orange00, Thank you for reply. Apart from the durability, half the reason that I want to change to metal is the look of the truck....... . I hope I can make this truck with all metal and carbon material. But I think I may pick the wrong truck as Spider is not so popular and after market hop up is not many.......