I have Eibachs on since the 5K miles mark.
At 8500 miles the fronts were unusable due to feathering, replaced.
At 17,xxx miles, fronts replaced again due to feathering...
At 26,500 miles, seems like feathering is coming back.
The Eibachs do NOT solve the feathering issue. They do improve the ride tremendously. I got them to get rid of the "bunny hop" and because maybe they would help with the feathering. I love the ride, the stance, the turns, etc.
The dealer will NOT honor the feathering TSB because of the Eibachs, although they don't cause it or cure it. I got camber arms (front and back) just to make sure I get the car back in spec.
After Eibachs I was very small out of camber front and back. I got Kinetix control arms and fixed both, just so that Nissan can't say it is the camber issue. I then got Toe cam bolts to adjust Toe per the latest TSB.
The only thing left for me is that I have always used "old thread" RE040s. I don't know if I will try new thread ones next time or might just switch to other (harder) tires. We will see.