[Ed Wright]

I know people who had axles "rifle drilled" to lighten them, and saw zero E.T. changes.
Un-sprung weight is not as desirable as weight suspended, or "sprung-weight", I am told.
Weight changes on larger diameter components would be more noticeable due to effects on inertia.

Lighter axles, as I have been told, "can't hurt a thing."
I have some very bright friends. Wish I knew everything they know.