hi and welcome to the club,i to have a 2003 is200 my alloys started after only 12mths, you could only just see it ,and it was only on the front but lexus changed all 4 wheels, and it dose not matter about the curbing , but to get them changed the car must be no more than 3yrs old and 60,000 mls. ps my alloys are the 18inch alloys