When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Apologies if this is stating the obvious, but they can be sensitive to wheel alignment, have you have a 4 wheel geo done? Any sign of uneven tyre wear?
I'm guessing here, but a 40mm drop is quite a bit, did you look into a roll center correction kit?
Only asking since you've eliminated any rubbing/catching and wheel bearing issues it makes me think it's a geometry/alignment issue.
Another guess would be CV joints...