A123 5s or 6s runtime question

Hahah theres a few different thoughts there.

So basically, if I increase voltage, there will be a corresponding increase in amperage due to resistance etc, but provided that I re-gear to keep the amps down, I could end up with a little bit of extra run time, right?

I could just bite the bullet and run 5s2p but that makes for a very heavy battery on 1 side of the Revo. I have tried 2p before and the jump in amps was negligible, I'm just trying to avoid having a phat 10 cell pack in my car lol.

What about changing motors to a higher or lower kv? Would that make a difference in run times?