ahh interesting, I hadn't seen that style of lock kit before. It's very similar in concept to the factory non-hicas setup on the stagea.
I am not excited about the design of the brackets because they have a single bolt, and no apparent locating dowel or flanges against a locked surface. In any case, if a bracket with a bolt that big is moving it will not be a smooth "wiggle" but rather a sharp/clunk unless it is finger loose. also you would see scraping on the paint of the subframe if it was moving.
given the inner and outer rod ends are bearings and new they should be easy to check for slack. is the outer end now a bush of some sort instead of the factory ball joint? If so, it might be the whole subframe that is shifting relative to the car?