I have an IS300 Sport. My front tyres are fine and still on 4mm at 32000. I replaced my rear tyres at 30,000 miles even though they were still on 3mm. The reason was because although they looked fine the insides had gone done to the braiding and were illegal but I did not realise this. When I spoke to Lexus about it and asked if I needed a 4 wheel alignment they just said it was an issue with all IS models and it did not need 4 wheel alignment. Any suggestions?