okay what are you running to get low voltage problems im assuming some aftermarket insane wattage car stereo amps
what kinda of voltage readins are you getting at the batt terminals , at idol, under load , car off , also take a voltage reading at your car stereo amp, if you battery is kickin out less then 12. 2 volts or so its a bad battery also the big 3 deal my solve alot of problems for example after i did that upgrade i get almost 14 volts to my amp
becuase i have an 02 tahoe i think its got a 105 amp alt i got a brand new optima and all zero guage wiring and my 5 channel is like 1300 watts rms my lights or guages dont fliker wehn the bass hits nothing no problems
and if you have an insane stereo system there is also a dual alt kit so you can just install a second alt right next to the current one