But first see his upgrades dude...He is done grounding and big 3 in car,Just capacitor is need and back up will be great...!
My czn running 2 x 307D4 subs in his cultus with solid Audio F-10D amp on just 65 amp battery,else everything is stock and electricals showing rating around 11.5,@ pretty higher volumes...!
@poster:-
New cap of 2 farad local one cost around 8~9K...But then its better to invest some more and go for stinger 1 farad,It will literally blew away local 2+ farad cap...!