Installed my GR+Pros this weekend and they are doing the same thing. Lubed the ball joints with lithium grease with no improvement. Springs are preloaded two full turns, as specified in the provided instruction sheet. Still need to torque the top nut. I'll post an update if I see any changes.
Do all Stance coilovers do this or are we just getting a bad batch?
Also, as far as impacting the top nut, I'm not saying I'm for or against it, but SPL's instructions for their KTS coilovers say to impact it on a light setting:
http://www.splparts.com/doc/SPLCoilover/default.htm