I haven't visited this thread in a couple years, but I see nothing has changed unfortunately.
I don't know if it is in this thread or another, but I believe a couple people have gotten steering rack work for this issue. If I recall, at least one guy claims the issue came back after the work.
I have been riding pretty smooth since the dealer put on Michelin LTX and took it to the regional service center for balance. They still couldn't get it aligned right though and I had to visit a local shop for that. This was 18k miles ago.
Now I am about to change wheels and tires and add 5100s. I am expecting my vibration to come back. Just don't know how I am going to fix it this time.
Seems like many claim that a lift has fixed the problem, while a few say that it hasn't. It would be interesting to know exactly what parts were replaced and what they were replaced with when doing suspension work, as this varies greatly from one person to the next.
Also, why hasn't anyone gotten a class action together to get Toyota's attention? This has been going on for way too long and happening with way too many vehicles without a proper solution. This website is amazing when it comes to finding solutions to pretty much everything 4Runner related, but this issue has proved to be a confusing mystery. For every one person that claims that they did a certain thing to fix it, I could find at least one other person that claims that that same thing did not fix it.
If these trucks are just hyper sensitive to balancing issues, well in my opinion that still falls on Toyota as a design flaw. With all the balancing tech, nothing in this century should be this hard to balance.