new 92 maxima alternator

I have a 92 maxima and i put a sounds sytem in; 1000 watt amp with a 1200 watt sub, 2 300 watt speakers, and 2 130 watt speaker with a 200 watt headunit. I have had it installed for about 6 months and its been fine however a few weeks ago the battery light went on so i charged it. Then the next day it went on again so i changed the battery however it still goes on so i am thinking its the alternator. Also when i turn the sub on the batterlight blinks to the beat. Anyway I am gonna try to save money by going to a junk yard and buying a used high amp one. Will any one fit or does it have to be a specific kind?

...going to a junk yard and buying a used high amp one. Will any one fit or does it have to be a specific kind?

Anythin that fits in, fits in. Most wont before 'arranging' mounts, plugs, pulley.