Ok so I took my 02 mustang for inspection today and it didnt pass because my tires are worn out. I just replaced my tires back in November. And as hard as it may be to believe, I dont stomp on it alot. I have 18inch rims with tire size 255-45-18 Z rated on it. Basically it cost 660dollars to replace all four. At this rate im going to be doing this twice a year. I am thinking about pruchasing smaller 17in rims that will have a 245-45-17 HTR rated on em. This setup with tires and rims will run me 979 bucks. If I were to do this, in the long run, would it save me money to go with these smaller rims? would the tires last longer then the 18's? Whats the difference between a Z rated tire and an HTR rating? If there are any tire experts on here your help would be great!