[9/11 RSX-s]

The so called 'grounding kits' do NOTHING to improve this specific path. Anything to the battery ground does not improve current return path while the engine is runnning since the alternator/ its mounting bracket is the source of + voltage & thus the return path has to be good going back to it.

So you are saying that running a wire from the wiring harness ground point on the manifold to the battery would not make a better ground? That it would be better to ground to the alternator bracket or what ever it is attached to (block/head)?