Hmm. Weird. Any vibrations, howling or wines? Wonder if the blocks are loose? Removing them could narrow things down any way.
If something was loose at the diff I would think there would be noise going down the road?
Hopefully it's a simple. Maybe something in the differential is sticking?
The subframe connectors should be nice as Hotchkis makes a nice product. Unrelated to the issue.
How does the the clutch pedal feel? I have the same set up as you but I am several months away from trying it out? What gear ratio?
Excited to see how this goes. I am on the same road just not as far. LOL