Ulykus
For the AI and actuators inside a mechro: this could be karavan technology, binding mechros as close to karavan as zorai are bound to kami. A mecho could deteriorate (in RP) if he decides to renounce karavan religion because he lacks maintenance and replacement components.
Shame you don't like it... another manga movie about cyborgs would be Battle Angel Alita, a movie James Cameron is thinking of remaking just like Avatar.
I am not to worried about the metal parts; graphene (carbon atom sheets) can replace metal easily, since graphene has even better properties than metals.
The Mechro technology is created to make the summoning of dead animals possible, so it would be weird if there wouldn't be any nano-selfrepair-bots there to fix the tech, but then again... yeah... we could make them addicted to nano-bots; hence technology junkies! :D Awesome...