OK, I'll go read the other post. I missed it somehow.

Serum,

Thanks for taking the time. Just to discuss the points that you made above for a sec. If I understand correctly, the 5K pack will have more stored energy (= mAh?) than the 3.2Ah pack, but the higher voltage system will expend LESS energy doing the same job as the 4S system?

If that is the case, then my point should still be valid. You also need "better" battery packs with a 4S system than you would with a 6S system. Notwithstanding the price of a controller to handle 6S, getting into a 6S system would make for sense for the more budget consious than getting into a 4S system.