maxx430

I need one for an aftermarket subwoofer I plan to put in and replace the stock subwoofer . I have a ML sound system if that makes a difference. 1) I noticed some LOC has 2/4 channel and would say 50watt per channel. Does it really matter about the watt per channel? I thought his was only converting the signal. 2) I noticed some had a ground and turn on/power wire. Do I need an LOC with those options?

Much Appreciation