I have just changed my run flat tires after 23,000 miles. The last 5-6,000 miles have been awful. The noise generated by the tires is annoying. The cost of these tires is highway robbery. My dealer wanted $360 per tire. I think Lexus made a big boo boo with when they designed this car. No room for a spare, and poor lifespan and tremendous expense involved in replacing them. I even tried to have conventional tires put on, and the dealer said he could not do this since a special kit that is in short supply is necessary to accomplish this task.