Alright guys. I've done some searches and haven't found exactly what I'm looking for, but...

I have a Sony CDX-MP70 deck hooked up to the stock speakers. I have two JL 12w6's on a RF 2ch 500watt amp. Running on 2 ohms a piece getting about 250watts per sub. Would it be wise to get a cap or do you think I would be able to run fine? Estimation would I be having to replace my battery and alternator often if I didn't have a cap? Thanks guys, I know some may say get a new alternator but why not spend a couple less and get a cap. I want to figure out before connecting my amp and subs...

 

I did not need one I have two alpine v12 and a jl10w7 plus a alpine screen and i have had no problems of late

 

500 watts shouldn't necessitate a cap. you can get a .5farad one if you want, just to keep everything clean and help control headlight dimming at idle, but it is not needed. replacing new alternator would only be necessary once you start drawing too much current.

my buddy is running 1000watts to a sub, 325wattsx2 to mids, and 50wattsx2 to tweeters, with a 1 farad cap, an optima deep cycle battery, stock alternator, and underdrive pulleys (which pretty much severely cut accessory power). his system is fine, gets some headlight dimming at idle but that's it.