See Azimov, this is what i was afraid of.

Adding parallel batteries will do nothing to your current. It will only give you longer run times. It will be the same current as 1 battery. 10 batteries in parallel will not give you any more current than 1 battery will.

FETs will undoubtedly be better than the stock transistors. Also, to my knowledge, I haven't seen anyone bypass or remove the voltage regulator. I'm pretty sure people don't know where it's being done.