Its kinda the same as the Ecotek phenomenon, good looks, rave reviews and scientific mumbo jumbo - but in the end, it doesn't achieve anything, and in most cases is just plain detrimental.
Capacitors can discharge a decent amount of power, but it is incredibly brief (like when a camera flash goes off), but it can't be sustained, it must be charged up again. Think along the lines of a disposable camera (poor analogy, but it works), between flashes the cap energizes...but its this period where it is detrimental, because it is drawing necessary voltage/current from the battery. Yes, they charge up very fast - but don't serve any purpose, the battery could provide that hit of power, rather than the cap providing the power, discharging the battery to recharge (whilst the amp still needs power), then dumping the power again.
Money is
always better spent on a good battery (Optima Yellow Top etc.) or uprated alternator, caps simply hinder performance.
The only place a cap should be in your ICE is part of a crossover for the speakers. My advice, sell it on eBay and pocket the cash for future upgrades (because once you get that first taste of bass, you can't stop
).
So to answer your question,
there's no harm in having it in there though is there? Yes, there is.
