Yea.. in a way lol.. but who knows.. If the money is ever available I would do it.. at least another battery? If everything does well when you add you stereo in, then keep it the same.. just an opinion from me.. thats all.. took me FOREVER to upgrade electrical.. lol money was never there to do it thats why..
You'll be okay. I'm running approximately the same amount of power off of a stock 130 amp alternator. I get slight dimming at full volume, but I haven't done the big 3 or gotten a car audio battery.
Go ahead and install it alongside with the big 3 and if you still feel your amps are starved of power, upgrade the alt.