hey i dont want to replace my alt because i dont know how much hp im gonna lose plus i dont have too much money for the alt. so i have a red top and i have other batterie then i have two amps one is 2k rms i did the big three and the light dim a lil at full volume i think my alt is 130amps and like i said my amp do not make my car light dims too much is stable but it dont put alot of power because of the current received to the amp so can i put 2 batteries and two amps on my stock alt with the big 3???
More weight doesnt affect Horsepower. It just affects How much your engine has to "Work" to get your car moving. For Example a 3500 Lb. Car has to "Work"Harder than the same car (Engine,Etc...) with a 100 Lbs. worth of stereo equipment. It Affects your cars Horsepower/weight Ratio.
Recently I've been seeing some cars that use 8 and 10 gauge wiring for the alt to battery!! The big three will help if the existing wiring is too small to handle the output of the alt or if the existing wiring is falling apart.
Also, the benefits of a HO alt, in my opinion, are completely worth the 1-3 hp you'd be losing like bassman said.