You got it all right.
J4 can ground either location, depending on your installation.
You can leave your amp(s) wired up as it/they are currectly.
J1 - battery possi.
J3 - 12v ignition
J4 - battery negative of just ground with amp?
J6 - Amp, left pin is remote right pin is ground.do I have to ground it? Can I just not use the remote pin into the amp and leave the amp grounded?
I have no pic of the M2 so I hope you all know what Im talking about!