Airhead starter ramblings

We are quick to pass judgement on OEM batteries and starter motors getting sluggish.
How many of us have thought of replacing the battery cables to improve conductivity?

I fit an extra earthing wire so that I can not have to rely in correctly torqing the problematic earth/speedo cable / gearbox vent screw.
Anyone have contacts in the industry that could make up longer earth cables to reach the engine mount where the clutch cable adjusts?