ive always been taught that the capacitor should be isolated for the subwoofer amp only. thus using it as a power distribution block for BOTH amps would be the wrong way of wiring it in. im not saying you CANT do it… im saying theoretically, that you shouldnt. the capacitor is like you said, a temporary stored source of power for when there is extra strain on the vehicles electrical system. you arent really going to get “strain” from an interior amp… a quality power distro block, a 1-2 farad cap, a quality GROUND distro block and separate wiring is how it SHOULD be done…PROPERLY.
joey, you dont have a clue what you’re talking about in the audio section… go elsewhere and brag about how fast your civic is going to be this year or something.