changing the stock power and ground wire to the battery

you are right, it's not a huge system
but i'm anal about it, not so anal that i had to buy all brand name top of the line components... but anal enough

my sub amp is a Kenwood kac-718 and at 4ohm has an RMS rating of 120watts
the manual says that it draws 15amps, i don't remember what size fuse it has

my other amps are Rockford Fosgate punch 100z2's
each of them are 25watts X 2 channel RMS
i'm not sure how much current they draw but i would guess it's less than the kenwood

i have a 4awg cable running to my trunk that goes into a distrubution block and 8awg running to each amp
each amp is grounded with 8awg
the stock wiring off the battery is 3awg coming from the alternator and 6awg going to the underhood fusebox
i'm not sure of the size of the battery's ground wire, but i know it is no bigger than 3awg

i just thought that for the sake of keeping things equal that you should have the same gauge wire grounding your battery as the gauge you are running off of it

i agree that it is probably a little unecessary but would it hurt anything to replace the stock wire that goes from the alternator to the battery? or the stock battery ground?

thanks
Sean