a capacitor is totally a waste of money. your amp will probably draw enough power at high volumes that it will either stall your car or shut off(the amp i mean). if you don't plan on competing at all or really turning it up extremely loud (in other words, daily driving) then you should probably be fine. if it turns out that your lights are dimming when the bass hits, take the alt out, take it to an alt shop, and have them rewind it like 20A or so and that should help alleviate your problem without spending $400 for a 200A alt. usually alt shops will rewind your alt for something like $1/A. i would have had mine rewound, but taking a 75A alt to 160A+ would probably have taken some act of god. i just opted to get a 200A from PA Performance, which specializes in mustangs.