I bought LS430 in 02 and currently it has 106K miles on the odometer. I hope somebody could offer some advice to my question: I recently noticed, during my regular highway commute, a sound consistent with a tire being slightly out of balance or perhaps having a flat spot. It's coming from the rear. I checked with a tire place and they couldn't find anything wrong with tires, but they said I'll have to live with it until the next replacement (Toyo Proxes TPT with 36K). After a week, they rebalanced all 4 tires and replaced the rear ones. The sound did not go away. Could this be linked in some way to suspension wear and tear items. I do mostly highway driving. Any suggestions will be greatly appreciated.