While they do discharge faster than a lot of batteries, most caps actually recharge slower than a battery does, and will put a much harder strain on your charging system. If you want better power- invest in a quality HO alt and wiring upgrade under the hood, and another battery. Putting a capacitor in your system is like putting a band aid on a broken bone. It's only there to mask the real issue. Don't expect it to bring up your voltages, which is what your amp needs to keep functioning a long and healthy life... That is why having that alt is the key to a good sounding and lasting system. Most stock alternators are only rated for a few amps more than the car requires from the factory, and then you add in another 1000-2000+ watts in stereo gear onto that load? 99% of people do that simply because someone told them just to "get a cap it will fix the dimming." It does in some cases, but only by covering up the real problem at hand.