I currently have Kicker subs and kicker amp. Was disappointed with the sound from the rear facing subs.
The subs are configured; Head Unit SUB RCA jacks to amp. Amp configured for base to speakers.

I called Kicker and spoke to tech. Explained the set up and he told me to do two things.
1) stop running speakers from RCA whenever possible. The RCA is prone to external electrical noise. Wire speakers to the harness. It will have its own ground. Eliminates any whining

2) leave the subs as rear facing but run them as mid base from the rear speakers fron headunit

rear speakers from head unit to amp. Amp configuration remains unchanged.

HUGE Improvement.

I really want to try the front facing speaker adapter when/if they becomes available.
super happy with the improved sound. Have ordered Dynamat for the doors. I was on the highway today and felt the sound was a lot better.