Let's pontificate for a minute, because there's snow on the ground and the windchill is 5 degrees. I have zero desire to turn wrenches in that nonsense.
If it is indeed the CV angle, the fact that three separate sets of CV axles (two of them brand new) haven't really affected the issue tells me it's not a problem with the CVs themselves. If so many of you are running 3" of lift without these vibrations, then my 2.75" is within an acceptable range of angle.
What then, could it be? Remember, this started immediately after I lifted it. I didn't notice this at all with stock suspension and tires.
Looking at the FSM, I think it could be the outer bearing on the passenger side of the diff (circled below). There's a few millimeters of radial play at the inner CV tulip.
This is a video I made of the driver's side a few months ago before I installed the ECGS bushing, but it illustrates what I'm talking about. The passenger side doesn't have this much play but there is
some. It's too f-ing cold to go video the passenger side right now, but you get the point.
Another possibility is maybe the SPC upper control arms are pushing the knuckle too far away from the diff, which could pull the CV tripod towards the edge of the inner CV tulip. The UBJ is pretty centered in the UCA slot though, and the alignment is within factory specs. This could explain why it's done this across 3 sets of CVs but given the alignment specs, I think this is unlikely.
Could bad LCA bushings or wheel bearings do this? Literally every other wear item in the front end has been replaced within the last 8 months.
Would someone who doesn't have vibrations like this be willing to go look at their passenger side CV at the diff and see if they have radial play at the outer diff bearing?