So I'm currently in the process of planning a Big 3 upgrade, but a single thought has constantly run through my mind. On the chassis ground, with bare metal, would oxidation overtime not be a concern? How would one prevent this from happening?

 

It would be if it built up, but is often not a concern, strangely enough. there are many anti-corrosion pastes, sprays and gels out there which you could cover the ground terminals with if you think it may be a problem.