From my understanding the stator has a maximum output of 42 amps before regulated? I may be incorrect.I would be curious to see what the actual voltage output is at idle before the regulator.
Then see what the voltage output is at 3k, 5k, 8k. Just to see what it is putting out and regulated down to. I'm assuming the factory regulator is pmw (pulse width modulation). A pmw system basically doesn't use excess power. The voltage climbs up to say 50 volts at 8k rpm. The regulator only uses 14 volts.
A person could in theory design a system that would use a mppt (max power point tracking) system for regulation.
A mppt system would increase amperage output when the stator is producing excess voltage at higher rpms. The only limiting factor would be the size of the winding wire in the stator.
I haven't read a lot on mppt, so my understanding of that technology is very limited. If any of this is wrong, I don't mind be corrected. I'm not by my buggy right now. Otherwise I would try checking voltages for myself.