Going to a higher amperage alternator is not a bad idea, given the demands of your audio/video install. However, I'm not sure I would trust my electrical load demands on a JC Whitney no-name brand alternator.
If you are knowledable enough to select JL audio drivers, then you are certainly aware of the alternator offerings in the market that stereo competitors endorse...and they PUNISH their equipment!
I always say...you can't have TOO many aternators...
