Also, solved my rear end knocking. Turns out it wasn't the suspension at all but the rear latch. I tend to drive a lot with windows down sunroof open, yes even on the highway. I think years of air pressure pushing against it had loosened it up. Anyways, a bit of tessa tape on the latch solved it. I went ahead and did that on all the latches in the doors and seats. It really helped a lot to tighten things up. Bonus, the exhaust drone that would resonate the hatch also lessened. Much quieter with the windows up.
Still, would recommend the Koni's 100%. They really help a lot of the expansion strip THWACK you get on OEM. Should probably get the fronts done too. That might be next.