can the regulator in these be changed so they will charge a 16v battery?
or even can they be bypassed and maybe use an external reg?

 

Why do you want to run a 16v battery? None of the ECUs or wiring is capable of running it.

 

it is likely that everything in the car is capable of it except the alternator and battery. it is not that uncommon on heavily modified gm vehicles and the feedback i have heard is everything in the car works better, brighter lights, faster power windows, etc.
the higher voltage actually has less wiring requirement. that is the reason there has been talk of going to 48v systems in newer cars is the weight and money saved by using smaller gauge wire for the same devices.

 

Aftermarket ecus will easily handle 16v and fuel pumps and ignition systems especially love it

 

i say if you want to change your bulbs weekly, go for it.