Well. I have the exact same 'problem' that @Vlady has with my Lexus GS450 2013 (with AVS)
I don't really know how to explain but when there's any slight wind, the car is all over the place and i have to really concentrate to keep the car inbetween te lines. It's not my aligntment, rims, or tires. I have 4 new hankook tires, 4 rims that are perfectly straight and the car has been aligned several times (last time with a Road Force Hunter).
I let my mechanic look under the car to see if there were any obvious signs of wear on my suspension but he said the car looked super clean and he did'nt see anything strange.
This is not the first post which i can relate to, i saw some on the american forums aswell but i really need to know if someone has fixed this problem, otherwise i'll sell the car, for only this reason. i love it but i can't keep driving like this....
Please, if you read this and you know a solution let me know, i'd really appreciate it!