installation questions

I am a new installer and I need a few tips. I have a Punch 500 amp pushing two 10" kicker subs. I wanted to add a 4 channel amp that I have (Kenwood KAC 646)to run 4 infinity 6 by 8's. Can I run two power terminals off my battery? A 4 gauge wiring kit for the 500 watt amp and a 8 gauge wiring kit to the Kenwood or are there other options? I also have the Punch 500 connected using a factory converter, can I run another one for the Kenwood and will running these with factory convertors be a proble later when I want to buy another deck and run tweeters off the deck? Any suggestions woudld be appreciated; Sorry it was wordy.

well lets break this down.. 1. U can run a 2nd wire.. BUT u can also get a distro block and only have to keep the 4 guage. These will allow u to split the 4 guage into multiple 8 gauge outputs Power(Fused) http://www.knukonceptz.com/productDetail.cfm?prodID=BC-1428 Ground(Non-fused) http://www.knukonceptz.com/productDetail.cfm?prodID=BC-1448 2. as for using the Line Out Converters(i'm guessing u have a factory deck). I would use a pair. one on the front speakers and one on the rear speakers.   then do a pass through from the rear outta 1 amp to the 2amp(ie outa the 4channel to the 2 channel) ... no this wont be a problem if u choose to put in a new deck later. just take them out and wire up the rcas to the head unit, instead of the loc's.. i would also at that point get a head unit with 3 sets of pre-outs so u dont have to use that pass through and have full controll of all ur settings Driving a Bagged, Caddied 02 s10