I guess I grew up in the great stereo era too....I used a powermaster 75 amp alternator and then ran an additional 10 gauge bypass directly to the starter relay{complete with an "extra" factory style fusible link...All stock wiring, original circuits including the amp gauge intact...Instead of the stock battery terminals I used Raptor terminals and ran the stereo wiring from those through an unused firewall hole and back to the trunk to the distribution blocks...Two 10s in the trunk,two amps in the trunk 6x9s in the rear deck,kickpanel speakers, and 4 tweeters in the cabin...Used the original fuse block for the head unit only...
No capacitor for that build and the lights never flicker when the bass hits..I built another system and used a capacitor mounted in the trunk to keep the low amp alt from taking the hit with subs and it's held up nicely in that vehicle...