Some of the upgrades for the 2018 season are trickling in. This is the "ZL1 1LE-Spec Suspension Upgrade System (P/N 84352119)".
ZL1 1LE-spec suspension upgrade system. AKA the FEA bushing and arm kit. by
Ryephile, on Flickr
ZL1 1LE-spec suspension upgrade system. AKA the FEA bushing and arm kit. by
Ryephile, on Flickr
ZL1 1LE-spec suspension upgrade system. AKA the FEA bushing and arm kit. by
Ryephile, on Flickr
The kit contains 8 of the 12 control links, both rear knuckles, with bushings/bearings installed, and *all* the hardware you'll touch during the install. Within the rear knuckle, 3 of the 4 pivots are solid rubber bushings, and the lower control arm lcoation is a booted spherical bearing, just like the front lower control arm [pictured above also with booted sphercial bearing]. The radius arm or whatever GM calls it has a big multi-piece rubber bushing, the "inserts" are filling the holes by the main bushing.
The hope is that this kit gives an incremental improvement in dynamic alignment fidelity. I'm thrilled the front LCA is a bearing, that combined with the Moreno camber plates will improve steering precision markedly. We'll see how long they last; the fact they're very nicely booted and safety wired means they should last for a couple years.