a cap wont add performance. it only makes it easier on the alternator during bass notes supplying quick power stored in cap. generally 1 farrad for every 1000w. i would consider a monoblock amp designated for subs.. another place to upgrade w/out a lot of spending is wiring... overlooked by...
i have 2 dvc 2 ohm subs wired to 1/2 ohm. 750w rms ea. ..amp is 1 ohm stable. if i add a 1500w rms 4 ohm dvc wired to 2 ohm... will that balance work with amp? will power distribute evenly? or wil one thrive while others starve?