Running 8.5 +45, 9.5 +45 is not a problem (exactly 5mm difference between a +45 and +50) You're in the clear just as long as you go with a 245/30/19 rear tire. Since PSS's aren't produced in that size, you can run that 255 if you have your fenders rolled. Most likely you'll rub when you run over larger bumps or have many people in your car. I hope that helps you out.