depends a lot of your listening preferences, volume habits, etc.. 200A would provide about 2200 watts of power (not factoring in efficiency of amps) after the car's needs.
if you want to supply 5Kwatts of power, you'll need a second 200A alternator, and at least a couple Kinetik 2400 series batteries or equivelant. also, battery isolators, 0 or 00 AWG wire, and so forth.
^^^ Your question just got answered by the most knowledgeable member on the forum Mike
A few big batteries will be ok if you keep the volume at a moderate level most of the time. But if you play a 5kw system at full blast, a 200 amp alternator ain't gonna cut it.
you could probably not run the system half the time and charge the batteries then bump it to full volume for 30 seconds or something, just to see what it will do with more power and see if its worth it to you for daily use.