minimac

how many amps should i get? My alternator is bad for sure i just bought a new battery and got about 10 starts and now it won't start without charging the battery, i know its bad, and i have no idea what alternator is in there, i have found anywhere from 95-240 amps, i plan on putting a real nice, big sound system in it so im guessing that rules out the 95 amp... i was thinking 200, is that too big? thanks