I Just bought a 2000 silver MT with 79,500 miles on it. Today is day 3 and I am running 55.4 MPG so far. I love the auto stop. I have Michelin Energy Saver Green X tires on the front (165/65R14) and the correct Potenza RE92's on the rear. The front tires look new and the rear ones have some life left. Are the Michelins ok? Should I have all 4 the same? The Max pressure for the Michelin is 54 PSI (on sidewall). What PSI should I run (F/R)?