I have a sony xplod head unit running into my MTX JackHammer JH600 amp powering my MTX JH4512-X2D subs. These setup is in my 2000 GMC jimmy with stock battery/ alternator.
http://www.amazon.com/Raptor-C1-0FM-Farad-Capacitor-Digital/dp/B0009DTJBO/ref=sr_1_2?ie=UTF8&s=electronics&qid=1261054684&sr=8-2
http://www.amazon.com/Lanzar-LQ16CAP-Contaq-Farad-Capacitor/dp/B001D22P34/ref=sr_1_1?ie=UTF8&s=electronics&qid=1261054714&sr=1-1
I apologize for the other moronic answers to your question. Those people probably actually believe the crap that they wrote. In truth, a CAP is a quick discharge battery that will absolutely improve the bass response in your vehicle. By keeping the input voltage constant, the initial "punch" as well as long rolling bass notes will be improved. I have always recommended 1farad for every 1000 watts. Although this is probably over kill with improved amp efficiency, err on the "too big" side rather than "too small".
Hope this helps. Again, I apologize for the previous answers. Remember, this IS a public forum and you don't have to know the right answer to actually think that you do.
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