I am in a quandry about which tire to buy for my mostly track day 2011 GT. Car has full suspension and brake preparation and after 2 years of development the car handles great. I'm currently running a 19x10 Apex EC 7 wheel square set up with 255/35-19 Firestone Indy 500 tires. Yes I know the tires are too small but it's what I had on hand when putting on the wheels. Frankly I really like the 500's. They have very good grip, wear like iron and are affordable for a retiree. The down side is they can get greasey towards the end of a 20 minute session. Now that I've saved up the money I plan to go to a 285/35-19 square set up and I've narrowed my choice down to another set of 500's or Michelin PS4's. My quandry is the cost benefit trade off between the Michelins which cost $1600 or the Firestones which cost $1100. Being retired I can't buy tires too often. I'm also concerned all the chassis development was done on the Firestones. I don't know if the Michelins would require a different set up. Anyone's thought or recommendations would be appreciated.