can anyone recommend a good capacitor?

If you already have upgraded the alternator I would much rather spend the money on another battery in the back.Custom Enclosure Design

I agree with that fully. I would do an audio batt at the back first.

I won have room anywhere else for another battery, I don't even have room for my amps, they will need to be mounted to my trunk lid and the proper steps taken to ensure they will survive there. I will have 7" of space between my two boxes, enough room to stick a cylindrical cap if I decide to go with one, which i am reconsidering at this point. Its more about future upgradability, I want to reduce the chance that I will have to go back and tear something apart just to upgrade to better components. hence why I'm going with top of the line wiring, extremely HO alt, etc. With the parts I'm goign to be using, I shouldn't have to tear down my car again to run new/better wires if i upgrade my HU or something later on. Same with a cap.... do I need one right now?? I highly doubt it, but will I need one later on down the road when I decide to beef up my amps/speakers/etc? probably..... so since I already have the power to charge my system, and a capacitor, and am not looking to use a capacitor as a "miracle device" (I have a good idea of what they are for) I don't see the harm in having one already installed when I add more power. unless of course there is a down side that I'm unaware of, in which case I would like to be informed. Where can I learn more about capacitors?

car audio caps that is.

http://explanation-guide.info/meaning/Stiffening-capacitor.html

bigjohnny wrote: I won have room anywhere else for another battery, I don't even have room for my amps, they will need to be mounted to my trunk lid and the proper steps taken to ensure they will survive there. I will have 7" of space between my two boxes, enough room to stick a cylindrical cap if I decide to go with one, which i am reconsidering at this point. Its more about future upgradability, I want to reduce the chance that I will have to go back and tear something apart just to upgrade to better components. hence why I'm going with top of the line wiring, extremely HO alt, etc. With the parts I'm goign to be using, I shouldn't have to tear down my car again to run new/better wires if i upgrade my HU or something later on. Same with a cap.... do I need one right now?? I highly doubt it, but will I need one later on down the road when I decide to beef up my amps/speakers/etc? probably..... so since I already have the power to charge my system, and a capacitor, and am not looking to use a capacitor as a "miracle device" (I have a good idea of what they are for) I don't see the harm in having one already installed when I add more power. unless of course there is a down side that I'm unaware of, in which case I would like to be informed. Where can I learn more about capacitors?

You are right, there is no downside of having the cap. You don't ever need one, however, even with a high powered system. Most people will tell you that they are not worth the money which is usually true but if you know what the will give you then it certainly isn't going to be a bad thing to do. A cap has a couple of benefits to a system. Their main function is to stiffen the voltage of your system. A cap will act kind of like a shock absorber on a car. It will keep the voltage from jumping around quickly so it is steady. The link audiocableguy posted does a pretty job of explaining it.