67 Cuda 273 Alternator Upgrade Questions

I've had other posts about tapping into some ignition run circuits and adding a car stereo with great response. The summary of that activity was that I need to upgrade my alternator!

What needs to go along with an alternator upgrade (100A or such). Voltage regulator as well? I'm an electrical guy, but not an electrical CAR guy. I understand that the wire between the systems has to be able to handle the load, I'm just not sure about everything in between. What all is affected??

I've also been advised about making changes to the Ammeter gauge.

Thanks all.