Welcome to the lexus community , The tires will last 40,000 - 60,000 just do not drift around and stay away from fast acceleration , drive the car with care , you have a beautiful auto and it will treat you as you treat it , regular maintenance should always be kept on schedule , run flats are really not the best choice but do offer a feeling of security , seen as they are new get your wear out of them and then look at your options . I am not really convinced that tire pressure monitors are really necessary , check pressure with a reliable guage at gas fill or once every two weeks which ever you feel comfortable with . I personally choose Michelin tires , always smooth and reliable . Hope this helps you . B)