What concerns do I need to look into when running a high current alternator?

I want to install a large sterio system in my Road Runner.

I understand that I need to provide a capicitor for bass speakers.

My concerns are the danger/operability of the ignition and charging systems while driving (wires {size}, grounding). The powermaster alternators that output above 100 amps appear to be one wire systems and currently the car has the original electronic ignition with the external voltage regulator.

I do not believe that I have an amp meter-but would it be possible to fry somthing in the dash behind the gauge cluster?

I was taught that the loads on the electrical system only draw as much current as they need-but I am concerned with the output of a high amp alternator when there isn't a significant load {alternator temp?} OR a very large load.

It needs to supply ignition (accel super coil in the future with a MSD box), battery charging, wipers, headlights, (no electronic fuel pump for now-nor ever any electronic water pumps) air conditioning, speakers: 12's X2, 10's X2, and 8 smaller speakers & a 500 watt amp.

The current stock system seems barely adequate to operate the vehicle with head lights and wipers on.

I live in a extremely humid environment with a significant amount of salt in the air. Of the previous cheap cars that I have owned here on the coast of South Georgia, grounding wires and battery terminals require cleaning annually and I do well to coat the top of them with a di-electric grease.

Some of the vehicles drew current from the battery when the A/C, headlights, wipers were all on leaving me stranded when the car was turned off (until I figured it out).

-Thanks FABO for your help!