Hey guys
im a little new to car audio, but not that new to audi on general
My car set up:
2 12 Kicker cvr 400RMS/800 Peak
1600 2 channel Power Acoustik OV2-1600 amp
Sony Xplod Headunit, Pioneer 6x9 and Dual 6.5" speakers

I just got a new alternator(bout 8 month ago ))
im about to get a new car tho, so i dont want to spend more money on a new battery, and a big3 upgrade, but im goin to do that on my new car

My question is:

How big of a capacitor would i need for that setup(Subs), I know that 500Watt= about .5 Farad.
But do i go by 500W RMS, or by 500W Peak???

Thanks