How to add an AMP to the RL?

Let me see if i get the setup right to add a subwoofer and amp to the RL...by all means correct me if im wrong :)

Since no RCA for the AMP - you would have to have something like a AudioControl LC6i to jump from the existing speakers and "normalize" the signal. Then go RCA cables from the LC6i, to the amp. Then it goes normal from there. Is this correct? Is there anything else you guys would recommend besides the LC6i?

Thanks!