I've read up on how to calculate to see how much amperage your adding ontop of what the alternator can handle.

The nominal voltage of a car battery is 12V, reaching about 13.8V when charging (i.e., engine running). You take that number and divide it by the total RMS wattage your pumping. In my case my sub amp is 200 and my headunit is 20x4 = 80w. Thats 280w just for the audio being a 20amp draw added to the stock alternator that only does 65amps. This is constant as apposed to peek wattage which it will hit rarly. So my peeks are 50x4 (Hu) and 400w (sub) all being 43amp draw. This also doesn't include the other accessories that are all on at night such as the headlights and A/C since I'm in FL hehe.

If this is right then its meanning that at peek state its drawing more than 50% of my alternator amps just to keep in power which im sure is the cause of the dimming and the very low idle.

BTW... its a 98 Civic Ex with no vacum leaks

I've also read up on a trick said on this forum that you can do to see if your alternator is the main key problem. Just run the car, wait till its at normal opperating temp then put the radio up loud to where it dims the lights. Now dissconect the Possitive terminal to the battery. If the car dies out to a stall at that point then you are stressing your alternator beyond what it can handle.

I havn't done this yet but, I will soon to tell you results but, before I attempt this.. is this bad for the car or can a sudden spike of power short something?