Here is my recommendation to you based on my experience with ls430 and all diy that I did to all my cars.Assuming that you did an alignment and the person doing it didn’t notice any visual damages to any of the bushings, first thing I will strongly recommend you to do is to check the condition of your tires (!). What brand and for how long were they used for in your ls?Poor tire sidewalls and poor tire condition as a result of bad weather or heat will directly affect the stability of your car. You may have all the suspension remade and replaced, but with poor quality tires your LS will drive correspondingly asking you to correct traction at every point of time especially at high speeds.Second thing that I strongly recommend you to verify is your brakes. Uneven brake pad wear, excessive air in the system, poor brake discs condition or poor caliper condition - any of these four condition will significantly contribute to front end or rear end looseness. Some other cars that I owned did not experience similar symptoms while these conditions were present.Third thing that is worth to be looked at is either of: play in Lower ball joint, front rear Lca bushing, strut performance, difference in front left and front right ride height, steering rack bushing, variable steering mechanism, sway bar cushions and links, and correct bushings retorque.

Knowing that any suspension part is subject to wear and it is difficult to diagnose a problem by two or three sentences, what may be worth to look at in your cause is the following:

- Hub centric rings are usually not something that is required to have on LS.
- Wheels need to be torqued to a hub using right tools and right method to prevent vibrations from this source. Use hand to manually tighten all five bolts to ensure rim is centered, then apply 76 ft lbs torque from your torque wrench. Your wheels will be centered (if your lug nuts are good)
——- Tires need to be force balanced. This is a must on this car.
——- Tires should be made by reputable brand. Cheap tires will cause wandering, vibration, instability during turning, and excessive noise. Poor alignment will aggravate it.
—— Worn wheel bearing may either cause a clunk during turns, or trolley bus noise while accelerating, or “Low Tire Warning” if one of the tire takes significantly more effort to rotate than the other.
—— Old original ball joint or cheap aftermarket LCA ball joint will affect suspension performance as it may not function properly according to Lexus standards. Now, in case if this element fails under heavy load, the consequences will include body damage.
—— From my experience, upper control arms are subject to a tiny wear even after 100k miles compared to lower control arms.
—— What dealers never do to our LS, is verify the condition of steering rack mounts. I ve seen cars that had a problem with moving steering rack under pressure. It will cause floaty steering.

Let me know if you find any of this information useful.