Al, the Kicker has a little switch you have to enable for on set of inputs for all channels and your good.

Like sandm said just split to the JL amp.

A cap stores energy allowing you to have enough juice to run everything in case you overrun the system, you won't need one. We float more than ride and i've never drained a batt or had the amps go into protect and my system is rated right at 1600 watts peak. Of course i can't get anywhere near that before the wife beats me!