UPDATE - For my car at least.
Cliffs: Poly lower control arm bushings fixed my shimmy!
Long version: I'm pretty sure I could have fabricated an entire exhaust in the amount of time it took me to swap out stock rubber bushings for poly inserts in the control arms. What a huge pain in the neck! Little did I know, until delving into this project, that you need OEM front bushings with the tapered bar to properly use the aftermarket Powerflex bushing. One side of my car had a scantech lca, the other side had no casting marks but you could tell it was aftermarket. After burning all the bushings out, seeing the pins, searching the forums, the verdict was in. I had the wrong front bushing/bar that wasn't tapered in the middle. Out came the bench grinder and custom tapering commenced. Finally, after dark, and a lot of struggle I got both sides back together and tightened down. Took it out for a spin and cautiously accelerated to normal wobble speed, nothing. A little more speed, slow down, speed up throughout the normal erratic vibration range, nothing. Smooth as silk!!!
I will say, after having both wheels off prior to this and inspecting the lower control arms, I wasn't convinced that I needed new ones. You couldn't see any tears in the either bushing and prying with a bar on the joints didn't expose any excess movement.
So I'll throw this out there. If you have a RANDOM shimmy/shake through a small RANGE of speed that comes and goes unpredictably irregardless of LOAD, put in poly inserts or new OEM lower control arms.
I'm giddy that it's finally gone and excited to put on the new IPD anti-sways that have been sitting in the garage for 6 months.