nup, ur right, a cap doesnt really do much. Only reason i got it was that i got it cheap brand new off US for $100 AU delivered when theyre about $300 brand new here. + it has a ricey voltage display. When i had my old battery, it stopped headlight dimming quite a bit. I have not noticed any SQ difference though, i never have from loss of current.
About the impedence question, if u remmber back to high school physics where v=ir, when the resistance is lowered, ie. from 4ohms to 2ohms, u need more current to make sure the law holds. and power is composed of current and voltage (which is constant).
so an amp at 4ohms will produce less power than an amp running at 2ohms.
thnx, hope to get the s14 soon and install all this stuff! taking a long time though :~(( slim pickins