Charge rate

[zeropointbug]

Yah, precisely. Ideally, if you could increase the max charge voltage as you increase C rate. You can do this with A123's however, I usually use 3.7v/cell for charging 5 amps/cell for a 2p pack, and then 3.8v/cell, sometimes even 3.9v/cell at 10 amps for a 1p pack.

I would be interested in finding out how a G3 cell would handle a 4.3v/cell charge threshold at 5C rate. I could only do this using my programmable power supply however.

As resistance decreases in lipo cells even further, 4.2v/cell should be sufficient for 5C or more charging to get the benefit. Like you said, it is mostly limited by the cells Ri.