Single cab 2001 Mazda b3000, so little limited space, sub on back wall, amp under seat.
I currently have the Kicker 46HS10 powered sub, and was wondering if it is possible for me to add an amp to my system, to power the Polk Audio MM 572's I am getting.
First off, I am looking to put the JVC KD-X470BHS in as my receiver.
Second, does the attached diagram work for connecting the powered sub to the unit and other amp? And do I need the power block or could I tap into the existing because they would be running next to each other? What about the ground block?

Third, for connecting the remote turn on lead, would I just sever the current and put both ends into a wire-nut with the new end?
Finally, recommendations for amp?

Thanks in advance.