so would i be ok with a 400 watt rockford fosgate 10"sub, a 400 watt amp, stock radio, stock battery, stock alternator, stock etc?

 

yup, u're not even beginning to harm it. just as long as you dont bump the system and running off battery alone.

 

Hey, been awhile since Ive posted at this thread, I have new questions though...I got an Alpine Type R 10" sub for Christmas Im thinking about setting it up with a 1000 Watt mono block rockford amp...I figure if theres increased amperage coming out the battery I might start to run in to some problems? anyone know? is the Deep Cycle battery still going to be adequate for this set up? Or should I keep the stock battery and set up the power cap with it?

 

the Fit comes stock with a 90amp alternator, so with 1 10'' you'll be completly fine. Lights may dim a little bit but not much. Im running 3 MTX TS55-22 subs with an Audiobahn A1300HCT 1200 watt mono block amp, Panasonic Double Din Indash, playstation 2, and I have HID lights too, and if there was any lack of power my lights would flicker and they dont. So you would be fine.

Also adding another battery to your setup would actually increase the strain on your alternator. Since Optimas and other batterys are Wet Cell batterys they would lower your voltage and strain your alternator quite a bit. If your looking to add a battery, you should get a battery from a company call "Kinetik". Their batteries are made for car audio, so they they wont strain your alternator and they wont decrease your voltage, they will actually increase your voltage without the strain. And also they rest at a higher voltage then a normal car battery. They rest at 13V instead of a car battery at like 12.6V.

Their website is www.Kinetikaudio.com if your intrested.
if ya got any questions, i can def help you out.